Cambridge Natural History Mammalia/Chapter XI
UNGULATA (continued)—ARTIODACTYLA (EVEN-TOED UNGULATES)—SIRENIA
Sub-Order 10. ARTIODACTYLA.
Fig. 138.—Bones of the Manus—A, of Pig (Sus scrofa). × ⅓. B, of Red Deer (Cervus elaphus). × ½. C, of Camel (Camelus bactrianus). × ⅛. c, Cuneiform; l, lunar; m, magnum; m2, m5, second and fifth metacarpals; R, radius; s, scaphoid; td, trapezoid; u, unciform; U, ulna; II-V, second to fifth fingers. (From Flower's Osteology.)
The Artiodactyle or "Even-toed" Ungulates are to be distinguished from the Perissodactyla, and from other Ungulate groups, by a number of trenchant characters. The most salient of these, and that which has given its name to the group, concerns the arrangement of the digits. Instead of there being but one prevailing digit—the third, in the hand and foot, through which the axis of the foot passes, there are two, numbers three and four, between which the same axis passes, and which are perfectly symmetrical with each other. This type of foot has been termed "paraxonic," as opposed to the "mesaxonic" Perissodactyle foot (see Fig. 121 B, p. 235). It has been attempted to prove that the single prevailing digit of the Horse's foot is a fused pair of digits, and the state of affairs which characterises the Camel, where the two metacarpals or metatarsals are to an almost complete extent united, has been urged in proof; so, too, certain abnormalities, such as those called "solid-hoofed pigs." These latter are simply Pigs in which the two central metacarpals and the terminal hoofs are completely fused with one another. In some of such cases there is not the slightest trace of the union of the separate metacarpals and phalanges. Even the sesamoid bones, attached behind to the toes, are two in number instead of four. And, furthermore, the tendon supplying the bones is single, though showing traces of its double origin. Such Pigs often show the abnormality from generation to generation, and they proved convenient for those whose scruples would not allow them to eat the flesh of a beast "dividing the hoof" and not chewing the cud. More singular still, as showing a pathological approach from another side to the Perissodactyle condition in an Artiodactyle, is a calf, where the foot ended in three equi-sized digits, of which the middle one lay in the longitudinal axis of the limb. From the opposite side cases are known of a Horse with a split hoof and phalanges, thus presenting the most striking likeness to a Camel.
There is, furthermore, in certain groups of Artiodactyles (e.g. the Tragulidae) a tendency for the two middle metacarpals to unite, quite apart from such "sports" as those illustrated by the cases just set forth. And, as already mentioned, the union of the two middle metacarpals culminates in the Camel, Ox, etc. There is, however, absolutely no trace of such a fusion in the series of Perissodactyle animals known to us; and it would be by fusion rather than dismemberment that, as it would appear on this theory, the modern Ungulate foot has been arrived at. Of course the facts of Ungulate descent are absolutely destructive of any such comparisons.
As is the case with the Perissodactyles, the Artiodactyles show a historical series, the primitive five-toed condition being almost preserved in Oreodon, up to the most modern modification exemplified by the Ox, Sheep, etc., in which animals there are not even vestiges of the fourth and fifth toes. It has been stated, however, that the foetal Sheep has traces of those rudiments. The so-called cannon bone (the fused third and fourth metapodia) is accompanied in its fusion by an increase in length. At the same time the functional middle metacarpals push aside the rudiments and, forming a broad surface for that purpose, articulate with the magnum and unciform bones to the exclusion of the rudiments. This has been termed an "adaptive reduction." In the "inadaptive reduction" there is the same reduction of the metacarpals, but the rudiments still articulate as in the primitive Artiodactyle foot, i.e. Mc II with trapezium, trapezoid, and magnum; Mc III with magnum and unciform; Mc IV and V with unciform. This would appear to give greater solidity and consequently greater strength to the foot.
Fig. 139.—Dorsal surface of right tarsus of Red Deer (Cervus elaphus). × ⅓. a, Astragalus; c, calcaneum; c3, cuneiform; cb, cuboid; mIII, mIV, metatarsals; n, navicular. (From Flower's Osteology.)
The carpal bones of the Artiodactyla alternate in their articulation; the primitive state of affairs is not retained even in the earliest types. The femur has no third trochanter, so prevalent in the Perissodactyles. In the hind-foot the calcaneum has an articular facet for the fibula, which is not characteristic of the Perissodactyla. In the more modern forms, e.g. the Cervidae, the navicular and cuboid become fused into one bone; and there are even further fusions which will be referred to later as characteristic features of different groups. It is interesting to notice that the reduction begins earlier and is clearer in the hind-foot than in the fore. One can see how this may be purely adaptive, the push of the hind-legs in running needing a firmer support. In Hyomoschus this is the case. The hind-limbs are provided with a cannon bone, while the metacarpals of the fore-feet are still free.
The number of dorso-lumbar vertebrae is less in the Artiodactyle than in the Perissodactyle Ungulates. Whereas the former have but nineteen, the latter have, as a rule, twenty-three such vertebrae. The number of ribs varies from twelve (Camelus, Hydropotes) through thirteen (Cervus, Gazella) to fourteen in Dicotyles, Giraffa, etc.
The curious form of teeth known as "selenodont" is characteristic of the Artiodactyla, though only found well developed in the modern forms, and of those only in the Pecora. The more primitive forms had "bunodont" teeth with typically four tubercles (if we except the tritubercular and but little-known Pantolestes); and the intermediate "buno-selenodont" type characterises such groups as the Anthracotheriidae.
While the stomach of the Perissodactyles is always a simple sac, it is complicated, or shows signs of complication, in the Artiodactyles. That of the Hippopotamus is divided into two chambers; there are three in Tragulus, and four in the typical Ruminants such as Cervus, Ovis, etc.
Had we to deal only with the still living genera of Artiodactyles, it would be easy to sort them into two groups on the characters of the teeth; for the Pigs and Hippopotamus are provided with tubercular molars; they are bunodont. The Deer, Camels, Oxen, Giraffes, etc., have selenodont molars. Besides, the latter are "Ruminants," and have a more complicated stomach. The existing Chevrotains forbid a more trenchant division, since they are, as will be pointed out in due course, somewhat intermediate in structure; the feet are more Pig-like, and the stomach is not so typically Ruminant. In any case such a division is prevented by certain extinct families which are perhaps ancestral to both. They have teeth which are not quite bunodont and not quite selenodont. These teeth have been termed buno-selenodont or buno-lophodont.
The distribution of the living Artiodactyles presents us with some interesting facts. The vast preponderance of species occurs in the Old World—34 in America as against over 250 species in Europe, Asia, and Africa. The Neotropical region has no Oxen, or Sheep, or Antelopes. The latter are confined to Africa, Asia, and certain parts of the Palaearctic region; they are vastly more prevalent in Africa, where they take the place of the totally absent Deer. The Pig tribe is almost entirely Oriental and Ethiopian in distribution, only one form, the European Wild Boar, ranging into the Palaearctic region; and the two species of Peccary are found in both North and South America. Broadly speaking, the Ethiopian region is the headquarters of the Artiodactyla. But the great island of Madagascar has but one form of Artiodactyle, a Pig of the genus Potamochoerus.
Fam. 1. Hippopotamidae.—The family Hippopotamidae contains of existing genera only Hippopotamus, for the Liberian dwarf Hippopotamus is not now regarded, as it was formerly, as the type of another genus, Choeropsis. The reasons for its former separation were the loss of the outer pair of incisors and the different proportions of various parts of the skull. This little Liberian animal has, however, been shown by Sir W. Flower to possess the missing incisors occasionally; and as to the proportions of the skull, it is exceedingly common for small animals to vary from larger relatives in this way. Hence, considering the characteristic features of the Hippopotamus and the fewness of species, it seems unnecessary to divide it up further. We shall therefore only recognise one genus.
The Hippopotamus at present is African in range, and confined to that continent. But quite recently it inhabited Madagascar; and further back still in time the existing African species, H. amphibius, ranged into Europe; there were also Indian forms, which were contemporary with the Stone-age man. The Common Hippopotamus is a great thick-skinned beast with but few hairs. It has four toes on each foot, a complex stomach, but no caecum. The strong incisors continue growing through life, as do the great canines. The number of incisors is two on each side of each jaw. Some of the extinct species had six in each jaw, and they were distinguished as a genus Hexaprotodon, contrasting with Tetraprotodon, until intermediate conditions were observed. Choeropsis, as already observed, was a still further reduction of the tetraprotodont type. The molars (the formula is Pm 4/4 M 3/3) when worn show a double trefoil pattern. The orbital cavity is encircled by bone. As with many other aquatic mammals the kidneys are lobulated.
Fig. 140.—Hippopotamus. Hippopotamus amphibius. × 1⁄40.
A very singular fact about the Hippopotamus is the production of a "bloody sweat," a carmine-coloured secretion, containing small crystals and corpuscles, from the skin. This coloured fluid has of course nothing to do with blood.
The animal grows to a length of at any rate 14 feet. The limbs and the tail are short. Like other aquatic animals the nostrils are on the surface of the head, and can be closed when the animal is under water. When it reaches the surface of the water after a prolonged immersion, it spouts like a Whale. Sir Samuel Baker says that ten minutes is the longest time that the Hippopotamus can remain below the water. It is frequently a dangerous animal to encounter, as it will capsize boats, and even bite large pieces out of their bottoms; with its huge teeth it can and does attack and destroy human beings. The Hippopotamus not only swims, but can walk along the bottom of a river with great rapidity. It occasionally puts out to sea from the mouths of rivers frequented by it; and it is supposed that in this way Madagascar was populated with Hippopotamuses, whose remains are now found in swamps in that island.
Fig. 141.—Wild Boar. Sus scrofa. × 1⁄12.
Fam. 2. Suidae.—The Pig family, Suidae, differ from the last in their smaller size, in the terminal nostrils and mobile snout, which is not grooved, except faintly as in Babirusa. They are generally hairy, but the Babyroussa is an exception, while Phacochoerus is but slightly haired. Though there are four digits, as in the Hippopotamus, only two reach the ground in walking. The stomach, furthermore, is simple, and (except in Dicotyles) there is a caecum. The kidneys are smooth, and the liver is more lobate than in Hippopotamus. The orbital cavity is confluent with the temporal fossa. The typical genus, Sus, is distributed over Europe, Asia, and the islands of the Malay Archipelago, reaching as far as Borneo and Celebes. The dentition is complete. A single species, the so-called S. sennaariensis, is from Ethiopian Africa, but it is not certain how far this animal may be an escaped species introduced by man. A very large number of "species" of Sus have been described, but Dr. Forsyth Major is disposed to reduce them to four if not to fewer species. He allows the widely-ranging S. scrofa, S. vittatus, and the eastern Malayan S. verrucosus and S. barbatus.
Fig. 142.—Pygmy Hog (from Nature). Sus salvania. × 1⁄6.
The Pygmy Hog of the Bhotans seems to be not entitled to specific rank, certainly not to generic (in the opinion of some), though it has been termed Porcula salvania. The Wild Boar of Europe is Sus scrofa. It was formerly quite abundant in this country; not merely are its remains exhumed from fens, caves and peat bogs, but there is ample evidence of its continuance down to a comparatively late historic period. Enactments are on record as to the hunting of these animals; there are places, such as Boarstall, whose names are clearly derived from the name of the animal, presumably once a native of the locality; and various documents all show the presence of the Wild Boar in this country down to so late a period as the end of the sixteenth century.
Fig. 143.—Wart Hog. Phacochoerus aethiopicus. × 1⁄6.
The African Wart Hog, genus Phacochoerus, is usually regarded as the type of a distinct genus of Pigs. This animal, "superlatively ugly" with its huge tusks and great protuberances upon the face, is chiefly to be distinguished from the genus Sus by these characters, and by the complexity of the last molar, which, with the tusks, are sometimes in aged animals the only teeth left. The complete formula is Pm 2/2 M 3/3. There are two species of this genus, P. aethiopicus and P. africanus. When enraged the Wart Hog is said to carry its tail directly up, and to present a ludicrous as well as ferocious appearance.
Fig. 144.—Head of Wart Hog.
The Celebesian Babyroussa, genus Babirusa, is an almost hairless hog with enormously upturned tusks in both jaws of the male. In the Wild Boar there is a hint of this, which is carried still further in Phacochoerus; but in Babirusa the upper tusks turn upwards before they leave the substance of the jaw, for which reason they appear to arise on its dorsal surface; the lower tusks are nearly as long. It has been found that the young of this Pig are not striped as are those of other Pigs. By means of the curved upper tusks this animal has been said by old writers to suspend itself to branches of trees, just as does by his downwardly-projecting tusks the male Chevrotain! There is but one species, B. alfurus.
From Sus proper the African and Malagasy Potamochoerus, including the Red River Hog, is barely separable generically. Their principal claim to generic distinction lies in the existence of a horny outgrowth arising from a bony apophysis above the canine in the male. These have been compared to the osseous "horn cores" in the extinct Dinocerata. But the Javan Sus verrucosus shows at least the beginning of a similar modification. The popular name of the animal is derived from the fine rufous colour of its pelage, not seen, however, in all the species. Dr. Forsyth Major recognises five species, of which only one is from Madagascar.
Fig. 145.—Peccary. Dicotyles tajaçu. × 1⁄6.
Fam. 3. Dicotylidae.—The Peccaries are generally placed in a different family from that of the other Pigs. This family, Dicotylidae, contains but one genus, Dicotyles, with at most two species. The name of the animal is connected with the dorsal gland; the animal thus appeared to possess two navels. The Peccaries, exclusively confined to the New World, differ from the Old-World Pigs in one or more important characters. They have only three toes on the hind-feet, and the stomach is complicated. Though the Peccaries have but small tusks they hunt in packs and are very dangerous animals to meet with. They owe, too, their safety from many foes to their sociable habits. Being nocturnal animals they are liable to the attacks of the Jaguar, which will speedily overpower and devour a Peccary that has strayed from its herd.
Fossil Swine.—The existing genera of the Pig tribe are also known in a fossil condition. Sus itself goes back as far as the Upper Miocene. Sus erymanthius, the Erymanthine Boar, is known from beds of that age in Greece, England, and Germany. This genus is not known to have had a wider distribution in the past than it has in the present. Dicotyles occurs in the Pleistocene of both North and South America, the regions which it inhabits at the present day. The genus Listriodon, also Miocene, is remarkable for having lophodont instead of bunodont teeth, that is so far as concerns the molars, which resemble those of the Tapir. It was European and Indian in range. A number of genera, more remote from the existing Pigs than those which have just been dealt with, are placed together in a special sub-family, Achaenodontinae. The type genus, Achaenodon, had a somewhat short skull for a Pig; and it is in general aspect and in the characters of the canine teeth highly suggestive of that of a Carnivore. The bunodont molars, however, are Suine, as is the form of the lower jaw with a rounded angle. This is an Eocene animal found in Wyoming.
Elotherium occurs chiefly in the Miocene of both North America and Europe; but E. uintense is Eocene. The orbits are completely encircled by bone in the more modern forms; this is not the case in the last-described genus, with which E. uintense agrees. The skull is also longer and more Pig-like. The zygomatic arch is powerful, with sometimes a large descending process, such as is found in Diprotodon, more faintly in Kangaroos, and in Sloths and certain extinct Edentates. The lower jaw has a pair of dependent processes near the symphysis, which suggest processes occupying a corresponding position in Dinoceras. The skull and body are heavy, but the two-toed limbs are slender. There is a smaller pair of toes behind these. The dentition is complete, and the canines are not inordinately developed. The brain is very diminutive. Perhaps E. uintense should be separated as a distinct genus, Protelotherium.
Hyotherium (which is regarded as identical with Palaeochoerus) has a sharp sagittal crest; the orbit is nearly but not quite closed. The canines are not strongly developed. The upper canines have double fangs as in Triconodon among extinct mammals, and as in the Hedgehog and other forms among living Mammalia. The premolars have the cutting and serrated edge of those of some other Pigs, a feature which gives them a curious resemblance to the "grinding" teeth of Seals. The molars are tuberculate, and like those of living Pigs. It is European and Indian in range, and Miocene.
The genus Choeropotamus has a complete dental formula save for the loss of a premolar in the lower jaw. Though it has lost this tooth, it is from an older stratum than some of those forms which have retained that premolar; it has been found in the Upper Eocene of the Isle of Wight and of the neighbourhood of Paris.
The American and Miocene Chaenohyus has lost the corresponding teeth of the upper jaw.
Homacodon is a genus consisting of several species, which has a bunodont and complete dentition. The molars are sextubercular in the upper jaw. H. vagans was of about the size of a Rabbit, and it appears to have had a curved neck. The limbs had five digits, as is so generally the case with Eocene Ungulates. It is known from the Middle Eocene of Wyoming.
The Selenodontia or Ruminantia form the second division of existing Artiodactyles. The characters of the teeth, which give them their name, have already been referred to. They also differ in that there are never more than a single pair of incisors in the upper jaw, and very usually there are none. As a general rule the third and fourth metacarpals and metatarsals become united to form a cannon bone. To this there is but one exception, the African Hyomoschus. Moreover, the second and fifth digits are nearly always rudimentary, and may practically disappear altogether. Here again the Tragulidae are an exception. The Ruminantia are so-called on account of the fact that they "ruminate," that is, after the food has been rapidly swallowed, it is forced back up the gullet and more thoroughly masticated. Associated with this is a complex stomach, which is divided into several compartments. This stomach has at least three compartments, as in the Tragulidae; but it has usually four. Its characters are illustrated in Fig. 146. The majority of the Selenodontia possess horns, which are partly formed of solid protuberances of the frontal bones. In the Giraffe they are somewhat different.
Fig. 146.—Stomach of Ruminant opened to show the internal structure. a, Oesophagus; b, rumen; c, reticulum; d, psalterium; e, abomasum; f, duodenum. (After Flower and Lydekker.)
This group may be divided into—A. Tragulina, Chevrotains; B. Tylopoda, Camels, Lamas; and C. Pecora, Deer, Antelopes, Oxen, Giraffes, Goats, Sheep.
As the Tragulina are undoubtedly the most ancient of the Selenodontia it will be logical to commence with an account of them.
Fam. 4. Tragulidae.—This family comprises a number of small Deer-like animals, which are really in many points more related to the Pigs than to the true Deer. They are known as Chevrotains; and the term "Deerlet," introduced by Professor Garrod, is certainly appropriate, since they have the aspect of very small and hornless Deer. If it were not for their Artiodactyle feet one might at a glance confuse these creatures with some Marsupial type. The family is Oriental and West African in range. The two genera (whose individual peculiarities will be considered later) differ from other Artiodactyles in a number of rather important characters.
Fig. 147.—Indian Chevrotain. Tragulus meminna. × ¼.
They are absolutely hornless in both sexes. The canines are present in both jaws, and are especially well developed in the upper jaw. The dental formula is I 0/3 C 1/1 Pm 3/3 M 3/3. In the skull the tympanic bulla is usually, as in the non-ruminating Artiodactyles, filled with loose bony tissue. The feet (usually) have the four toes of the Suina, and are therefore in a more primitive condition than in Deer and Antelopes. But as the middle metacarpals are fused in Tragulus (though separate in Hyomoschus) they are a stage further than are the Pigs, in the direction of the typical Ruminants.
The stomach is comparatively simple, thus offering intermediate characters between the Pigs and the Ruminants; there are but three separate compartments. A highly-interesting character is afforded by the placenta. This is in the present family of the diffuse kind, not presenting the separated and tufted cotyledons of the Ruminant placenta. This we may fairly assume is a further proof of the less-specialised characters of this group as compared with the Ruminantia, a view, however, which is not universally accepted. While the molars have the selenodont character of other Pecora, the premolars are more adapted for cutting, with sharp edges.
The genus Tragulus consists of several species (e.g. T. stanleyanus, T. napu, etc.), which have been aptly compared in external appearance to certain Rodents such as the Agoutis. The legs are delicate and slender, hardly "thicker than an ordinary cedar pencil." These creatures have got among the Malays a considerable reputation for astuteness, embodied in the saying, "Cunning as a kanchil." The male has tusks, which greatly contributed to the confusion of this creature with the totally different Musk Deer, Moschus moschiferus. It is even said to suspend itself by their aid to the branches of trees, and so avoid danger.
Hyomoschus (or Dorcatherium as it should properly be called) is West African. Its rich brown colour, with spots and stripes, is much like that of the Chevrotains, but it has shorter limbs. The only species is D. aquaticum, which is sometimes called, on account of its frequenting the banks of streams, the Water Chevrotain. Remains of this genus occur in Miocene and Pliocene strata of Europe.
The separate metacarpals, comparatively simple stomach, absence of horns, diffuse placenta, and spotted pelage are features which argue the primitive position of these animals among existing Artiodactyles.
Besides the two existing genera which have just been treated of, there are a number of extinct genera undoubtedly belonging to the same group.
Gelocus (Eocene and Oligocene in range) is a European genus known from France. It differs from the living members of the group by the fact that the second and fifth toes on both hind- and fore-feet are represented, as in certain Deer, by rudiments at the upper and at the lower end only; they are deficient in the middle. The middle large metacarpals, though closely applied, are not fused. The metatarsals, on the other hand, are, or are not fused, according to the species. A later form is the genus Leptomeryx from the Miocene of North America. This genus departs from the typical Traguline structure in more than one point. The tympanic bulla is hollow instead of being filled with cancellated bone; the cuneiform is not fused with the cuboid and navicular, though the latter are with each other; the lateral digits of the hind-feet are rudimentary. The magnum and trapezoid, however, are fused. In the fore-feet the middle metacarpals are separate, and the lateral less perfect metacarpals have toes. The metatarsals are fused.
Not definitely referable to the Tragulidae, but coming near to them, are the Protoceratidae. Of this family there is but one well-known genus, Protoceras, from the Miocene of North America.
The skull is singularly reminiscent of Dinoceras, with which this quite Artiodactyle genus has, of course, nothing to do. It merely exemplifies the phenomenon of "parallelism." In general form it is peculiarly long and low. There are three pairs of bony protuberances: one, the largest, pair are situated on the maxillae rising up just behind the implantation of the canine teeth; the parietals have a second pair; and a third much more diminutive pair of bosses are upon the frontals, near their junction with the nasals. This description refers to the male; the female has only traces of the parietal bosses. These were all possibly tipped or sheathed with horn or roughened skin. The dentition of this genus is precisely that of the Tragulidae, i.e. I 0/3 C 1/1 Pm 4/4 M 3/3. The orbit is completely encircled by bone; the auditory bulla is not swollen; the premaxillae are small.
The nasal cavity is very large and open, the end of the nasal bones anteriorly being situated at about the middle of the skull; this would seem to indicate at least a flexible and long nose like that of the Saiga Antelope, if not a trunk.
The brain was of good size, and quite well convoluted.
The limbs are constituted on the Traguline plan; in the fore-limbs the middle metacarpals are quite free from each other, and the more diminutive lateral digits are complete. The metatarsals are free, but with a tendency to fusion; the lateral toes are only represented at the upper extremity. The carpal bones are separated.
This animal, which was about the size of a Sheep, though of more delicate proportions, was allied not only to the Tragulidae but to the Giraffidae; it is impossible to refer it definitely to either family.
Fam. 5. Camelidae.—This small group of Selenodonts includes only the Camels and Lamas. The limbs are long and have no traces of the second and fifth toes. The fused metacarpals and metatarsals diverge somewhat at their distal ends. In the upper jaw is a single pair of incisors. The stomach differs from that of the typical Ruminants. The rumen has smooth and not papillose walls, and from it are developed the "water cells," diverticula with narrow mouths provided with a closing sphincter muscle. The psalterium is reduced to a mere vestige, and so the stomach has, as in the Tragulina, but three chambers. This, so far ancient, character in the structure of the Camel tribe is associated with another, also seen in the more primitive Ungulates, viz. the diffuse character of the placenta. A very singular peculiarity of this group is the fact that the blood corpuscles instead of showing the ordinary mammalian round contours are elliptical.
The genus Camelus, confined to the Old World, is made up of two quite distinct species, the Bactrian Camel, C. bactrianus, with two humps, and the Dromedary, C. dromedarius, with only one. The former species is Asiatic. It is a singular fact that neither of the species is known to occur in a genuinely wild condition. The so-called "wild" Camels appear to be invariably feral. The two species will interbreed; and there is at the Zoological Society's Gardens such a hybrid, which has the general appearance and shaggy brown hair of the Bactrian animal, but the one hump of the Dromedary. It may be that the Bactrian Camels of Lob-nor are really wild; but the desert contains so many remains of cities destroyed by sand-storms that these reputed wild Camels may be the descendants of animals belonging to the inhabitants of those cities. A strayed herd of Camels has established itself in a feral state in Spain. Otherwise the genus does not occur in Europe. The Camels are also represented in the New World. The genus Lama (Auchenia of many authors) belongs to this family. These Camels differ from their allies in the Old World by their smaller size, by the absence of the characteristic hump, and by the dropping of one premolar, the dental formula
Fig. 148.—Bactrian Camel. Camelus bactrianus. × 1⁄30.
being otherwise similar. A variety of names, Lama, Alpaca, Huanaco, Vicuña, have been applied to these animals; but it appears that the names are in excess of the number of the species. Mr. Thomas, who has lately inquired into the matter, will only allow two, the Huanaco, Lama huanacos, of which there are two domestic races, the Llama and the Alpaca, and the Vicuña, Lama vicugna. They are both South American in range. Not only is there a herd of escaped Camels in Spain, but the Spaniards attempted to introduce and acclimatise the useful Lama. The first Lama ever seen in Europe was brought in the year 1558 to the town of Middelburg in Holland; it was purchased and presented to the Emperor of Germany. Gesner gives a curious figure of it, representing the animal as a comparatively colossal beast submitting itself to the guidance of a dwarfish man. The habit of "spitting" of the Lama is well known. Augustin de Zarate and Buffon speak of the Lama as having no protection save this habit, which is more than a mere ejection of saliva: the contents of the stomach are forcibly shot at the object of its annoyance. It can also kick and bite. In the intestines (as in those of some other mammals) are found Bezoar stones, or Bezards as they are variously spelt. These were once valued in medicine, and even so lately as 1847 were, according to Gay, the historian of Chili, in vogue; these concretions, comparable to the ambergris of the Whales, were supposed to be an antidote to poison.
Fig. 149.—Lama. Lama huanacos. × 1⁄12.
Extinct Camels.—The earliest cameloid type is the genus Protylopus, of which we are acquainted with an imperfect skull and the greater part of a radius and ulna belonging to one individual, and most portions of the hind-limbs in other specimens. The one species, P. petersoni, was about the size of a "jack rabbit," and is late Eocene (Uinta formation) and American in range. The teeth of this mammal are the typical forty-four, and the canines are not pronounced, being incisiform in shape. In the skull the nasals overhang, as in the genus Poebrotherium. The orbit is not closed by bone. There is in this ancient Camel a trace of the supra-orbital notch so characteristic of the Camel tribe. "The vertebrae resemble those of the modern Lamas closely in their general proportions." The lumbars have the usually Cameloid formula of 7. This genus has but two functional toes on the hind-feet, the second and fifth being reduced to vestiges. It is interesting to note that the radius and ulna appear to remain distinct, except in very old animals, in which they come to be co-ossified in the middle only, thus foreshadowing their complete union in the next genus, Poebrotherium. The present genus, moreover, as well as Poebrotherium, was distinctly unguligrade; it has not acquired the characteristic phalangigrade mode of progression of the modern types of Camels.
Fig. 150.—Skull of Poebrotherium wilsoni. i1, i2, i3, Incisors 1-3. × ½. (After Wortman.)
The American and Oligocene Poebrotherium has been recently and exhaustively studied by Professor Scott. It was considerably smaller than a Lama. Its neck was long as compared with other Artiodactyles, but still shorter than that of the Lama. It was a lightly-built, graceful creature, with apparently some external likeness to a Lama. It is an important fact to notice that at this period, and for a long time after, there were no types referable to the Camelidae in the Old World. Though a Camel in many features of its organisation, Poebrotherium was "generalised" in many ways. Thus the metacarpals and metatarsals were not fused to form a cannon bone, and the two lateral digits were represented by splint rudiments of metacarpals and metatarsals. The dentition was complete. The skull though distinctly Tylopodan, also shows more generalised characters. Thus the orbit is not quite, though nearly, completed by bone. In the Camel it is quite closed. The nasal bones are much longer, reaching nearly to the end of the snout. The odontoid process of the axis vertebra is not spout-like as in existing forms, but cylindrical, though slightly flattened upon the upper surface. The scapula is described as being more like that of the Lama than of the Camel, though variations occur which approximate to the Camel. The brain, judging of course from casts, has those sulci "which are common to the whole series of Ungulates, and closely resemble those of a foetal Sheep."
Fig. 151.—Anterior surface of axis of Red Deer, × ⅔. o, Odontoid process; pz, posterior zygapophysis; sn, foramen for second spinal nerve. (From Flower's Osteology.)
Later in historical sequence than Poebrotherium, and structurally intermediate between it and Protolabis, is the Miocene genus Gomphotherium. It shows an advance in structure upon Poebrotherium, in that the orbit is completely encircled by bone, though the posterior wall is thin; the lower canines instead of being incisiform are curved back as in later Camels, and separated by a wide diastema from the preceding and the succeeding teeth.
Later in age than Poebrotherium is Protolabis, a Tylopod in which the full number of teeth is still retained; its skull presents no particular changes from the Poebrotherine type; the nasals, however, are somewhat shortened.
Later still in point of time is Procamelus. In this form we have apparently an ancestral stock, whence both Camels and Lamas were derived. The upper incisors are as in existing forms, but the first and second persist for a somewhat longer time. The skull shows two well-marked types of structure; in P. occidentalis there are more points of likeness to the Lama, in P. angustidens to the Camel. In both, the orbits are completely encircled by bone. The nasals are much shortened. The odontoid process of the axis is still more concave than in Poebrotherium, but not spout-like as in existing forms. This fact shows that the spout-like character of the Camels' odontoid process is not a point of affinity to other Artiodactyles—in fact the occurrence of the same form of odontoid process in Perissodactyles is enough proof of this. We must come to the conclusion that the form is adaptive in all cases. If we were not obliged on palaeontological evidence to come to this conclusion, the structure in question is just one which would be fastened upon as evidence of genetic affinity; for it is a resemblance in a small though distinctive point of structure having no obvious relation to utility. The metacarpals and metatarsals have coalesced to form the cannon bones, though a rudiment of one metacarpal seems to remain. The genera referred to appear to be on the direct line of descent of the modern representatives of the family. But there are other forms which are offshoots of the main stem. Such are Homocamelus, Eschatia, and Holomeniscus. The last two are Pliocene and American; the teeth are much reduced.
The Pecora are a group which possess so many characters in common that it is not an easy task further to subdivide them.
In all there are but two functional digits on the feet, and the metacarpals and metatarsals of these are fused. There are no upper incisors, and canines in the upper jaw are not universal, and generally small. Horns are confined to this group of the Selenodontia. The premolar teeth are of a simpler form than the molars. The stomach has four chambers, of which two may be regarded as belonging to its cardiac half and two to the pyloric. The former are, in the first place, a large paunch or rumen, followed by a smaller reticulum, so called on account of the network arrangement of the folds of its lining membrane. Connected with the latter, and constituting the first part of the pyloric half of the stomach, is the psalterium or "manyplies," so called on account of the longitudinal folds, like the leaves of a book, into which its lining membrane is raised. Finally there is the abomasum, out of which proceeds the small intestine. Garrod has observed that the chamber of the stomach which varies most among the Pecora is the psalterium. This chamber is specially large in Bos, and particularly small in the Antelopes Nannotragus and Cephalophus. But its variation relates more especially to the folds of its mucous membrane. These folds are of varying lengths and have a definite arrangement There may be as many as five sets of laminae of regular depths. The most simple psalterium is that of Cephalophus, where there are only two sets of laminae of different sizes, a deeper set and a very much shallower set; this form is termed by Garrod "duplicate." Most common is the "quadruplicate" arrangement, with four sets of laminae of differing depths. In all Pecora the liver is but little divided by fissures.
Fam. 6. Cervidae.—The Deer tribe is a very extensive one, and, with the exception of Africa and Australia, world-wide in distribution.
The Deer are absolutely distinguished from all other Ruminant animals by the existence of antlers, which are invariably present in the male sex, save in the aberrant genera Moschus and Hydropotes; in the Reindeer alone are antlers present in both sexes. The general characters of these appendages have been dealt with on a former page (p. 200), where they are compared to, or rather contrasted with, the horns of the Bovidae. These antlers, so characteristic of the Cervidae, are very variously developed among the members of the family. Thus in Elaphodus the antlers are very small and entirely unbranched. In the Muntjacs, Cervulus, the antlers are hardly larger, but they have a small anterior branch arising from near the pedicel, the "brow tine." In Cariacus antisiensis only one branch, the brow tine, is present, but it is nearly as long as the main stem of the antler, the "beam." In Capreolus capraea the beam bears two tines; in Cervus sika three; in C. duvauceli two of the three tines present bear secondary branches. There are other complications (some of which are illustrated in Figs. 152-157) of the simple antler which culminate in the complex antlers with their expanded "palms" of the Elk and the Fallow Deer.
Another highly-interesting fact concerning these same antlers is their gradual increase in complexity of tines and palm from the Miocene Cervus matheroni to the great Irish Elk of post-Tertiary times.
Beyond the antlers there seems to be no character of universal applicability which distinguishes the Cervidae from the nearly-related Antelopes. There are, however, a number of structural features which are nearly universally characteristic. Excepting Moschus (which Professor Garrod would not allow to be a "Deer"), no Cervine has a gall-bladder to its liver. All Bovidae (including Antelopes) have, with the exception of Cephalophus.
A small but constant character of the Deer is the existence of two orifices to the lachrymal duct. The genus Tragelaphus alone among Antelopes shows this character.
So far as is known the placenta of the Deer has but few cotyledons, that of the Bovidae many. But not many types are known.
The navicular, cuboid and ectocuneiform are often united. This is never the case in the Bovidae.
The first and second phalanges of the lateral (imperfectly developed) digits are always present except in the Muntjacs; they are never found in Bovidae. The Deer always present a light brown to a darker brown coloration. Elaphodus michianus is almost black. There is commonly white on the under parts and beneath the short tail. Some Deer, such as the Fallow Deer, are spotted; and the young of others that are uniformly coloured when adult are spotted. In some cases a winter coat, darker than the summer coat, is developed.
Altogether some sixty species of Deer are known, of which the preponderance are Old-World forms. The Deer of the Old World are distributed among the genera Cervus (all Europe and Asia); Cervulus, the Muntjacs (India, Burmah, China, etc.); Hydropotes (Eastern China); Capreolus (Europe and Central Asia); Elaphodus (Eastern China); there is one American Cervus, the Wapiti. The American genera are Cariacus and Pudua. The Elk (Alces) and the Reindeer (Rangifer) are circumpolar. The principal structural modification which occurs within the family Cervidae concerns the rudimentary fifth and second toes. In Capreolus, Hydropotes, Moschus, Alces, Rangifer, and Pudua there are considerable remains of the lower parts of metacarpals II. and V.; in the other genera smaller traces of the upper ends of the same bones.
The two most abnormal genera are Moschus and Hydropotes, more particularly the former, which neither Sir V. Brooke nor Professor Garrod allow to be members of the family at all. Moschus is usually placed in a special sub-family by itself, Moschinae, the remaining Deer being referred to another sub-family, Cervinae.
Sub-Fam. 1. Cervinae.—The genus Cervus comprises rather over twenty existing species, which, except the Wapiti (C. canadensis), are exclusively Old World in distribution. The principal features of variation in the genus, in accordance with which it has been divided up into sub-genera, are (1) palmated (Fallow Deer, Dama) or non-palmated antlers; (2) adults spotted with white at all ages and seasons (Axis), or in summer only (Pseudaxis), or not at all; (3) spotted or unspotted young; (4) existence or absence of rudimentary canines in the upper jaw.
Among the members of this genus, Cervus (Elaphurus) davidianus is interesting as having been first observed by the missionary Père David in a park belonging to the Emperor of China near Pekin. Its horns are remarkable for dividing early into two branches of equal length, of which the anterior again branches into two. Specimens of this Deer were ultimately obtained for the Zoological Society's Gardens.
The species of Cervus are fairly distributed between the Palaearctic and the Indian regions. The Palaearctic species, such as Lühdorff's Deer (Fig. 152), are mainly Asiatic. Cervus elaphus and Cervus dama alone are European and British. The former of course is the Red Deer, the latter the Fallow Deer. The Red Deer is reddish-brown in summer and greyish-brown in winter, with the white patch on the rump so common in the Deer tribe. The Red Deer is genuinely wild in Scotland, in certain parts of Devonshire and Westmoreland, and in the New Forest. At the beginning of the last century, according to Gilbert White, there were 500 head of deer in Wolmer Forest, which were inspected by Queen Anne. The antlers may have as many as forty-eight points; and a stag with more than the three anterior tines is termed a "Royal Hart." The Fallow Deer has palmated antlers, and is usually spotted. It seems to be an introduced species, common report pointing to the Romans as the introducers. It would be more correct to say "re-introduced," for fossil remains of this Deer have been met with.
Fig. 152.—Lühdorff's Deer. Cervus luehdorffi. × 1⁄15. (From Nature.)
Elaphodus contains probably two species, E. cephalophus of Milne-Edwards and E michianus of Swinhoe, both from China. The antlers are small and unbranched; the canines in the male are massive; it differs from Cervulus, to which it is closely allied, principally in the absence of frontal glands. The second species has a dark iron-grey pelage, and the late Mr. Consul Swinhoe described it as very Goat-like in aspect.
Capreolus.—The Roe Deer has fairly complex antlers. It is a small Deer and has spotted young. The common Roe Deer, C. capraea, is a native of this country. It is the smallest of our Deer, and its antlers only have three tines in stags of the third year. It is a singular fact about this Deer that though the pairing season is in July and August, the young are not born until the following May or June, a period which does not represent that of gestation. The germ remains dormant for some time before developing.
Fig. 153.—Mule Deer. Cariacus macrotis. × 1⁄15. (From Nature.)
The Muntjacs, Cervulus, form a distinct generic type confined to the Indian and the South-Eastern Palaearctic region. They are small Deer with spotted young, and short one-branched antlers placed upon pedicels as long as themselves. The canines are strongly developed in the males. There are about half-a-dozen species.
Cariacus is exclusively American in range, and contains about twenty species. There are or are not upper canines. The young are spotted. The antlers are occasionally very simple; in C. rufus and a few allies (placed in a special sub-genus Coassus) they are simple spikes without branches. In this genus, and in the nearly allied and also New-World Pudua, the vomer is prolonged backwards and divides the posterior nares into two. The bulk of the species are South American.
Fig. 154.—Chilian Deer. Cariacus chilensis. × 1⁄12. (From Nature.)
Pudua, just mentioned, comes from the Chilian Andes. It is a small Deer without canines and with minute antlers. Other generic names have been proposed for various species of American deer.
Hydropotes inermis is a small perfectly hornless Deer, living on the islands of the Yang-tse-kiang. The male has tusks; the young are spotted. Though, like other deer, Hydropotes has no gall-bladder, both Mr. Garrod and Mr. Forbes found the rudiments of one in the shape of a white ligamentous cord. Mr. Forbes has especially dwelt upon the likeness of the brain to that of Capreolus. The female has four teats, and produces three to six young at a time.
Fig. 155.—Water Deer. Hydropotes inermis. × 1⁄10. (From Nature.)
Alces machlis, the Elk or Moose, is a circumpolar species with palmated antlers and is of large size. The young are unspotted. This animal is the largest of the Deer tribe. The aspect of this creature is by no means that of a Deer, the long, thick, and rather prehensile upper lip not by any means suggesting the family to which it belongs; the legs, too, are ungainly through their unusual length. The Moose has a curious method of protecting himself from Wolves. Instead of moving about during heavy snowstorms, and being thus on the heavy ground an easy prey for these agile enemies, the animal forms what is known as a "Moose yard." An area of ground is kept well trampled down, and the animal contents itself with browsing upon the adjacent stems. The well-trampled ground gives an easy footing, and by his powerful horns the great stag is able to keep his enemies at bay.
Fig. 156.—Moose. Alces machlis. × 1⁄20.
Rangifer tarandus, the Reindeer, is unique among Deer by reason of the fact that both sexes wear antlers. These antlers are palmated. The brow tine and the next or bez tine are also palmated and are directed forwards and a little downwards. The young are unspotted. The pelage alters in winter. Like the Moose, the Reindeer is circumpolar. As is well known, during the Pleistocene period the Reindeer extended its range as far as the South of France. Even in the historic period it is said to have been hunted in Caithness.
Reindeer, like so many other particularly Arctic animals, have regular migrations. In Spitzbergen, for instance, the animal migrates in the summer to the inland region of the island, and in the autumn back again to the sea coast to browse upon the seaweed. These migrating herds have been stated to be led by a large female.
Fig. 157.—Reindeer. Rangifer tarandus. × 1⁄15.
Sub-Fam. 2. Moschinae.—Moschus moschiferus is a native of the Asiatic Highlands. It is 3 feet or so high, perfectly hornless, and with very large canines in the male. It is noteworthy that in Hydropotes, where the canines are also very large, horns are absent. These are examples, perhaps, of correlation. The musk sac (whence the name) is present on the abdomen of the male only. There is no crumen or suborbital gland, which is so generally (though by no means universally) present in Cervidae. But the male has, in addition to the musk glands, glands near the tail and on the outside of the thigh. Unlike other Deer, the lachrymal bone of Moschus bears but one orifice. The feet, so far as concerns the preservation of the outer rudimentary metacarpals, are of the more ancient type represented in Alces, Hydropotes, etc. A gall-bladder is present. The young, as in so many Cervidae are spotted; but the adult is of a greyish-brown colour.
Fig. 158.—Musk Deer. Moschus moschiferus. × 1⁄6. (From Nature.)
There is no doubt that Moschus is more nearly related to the Cervidae than to any other Ruminants. It is regarded by Sir W. Flower as "an undeveloped deer—an animal which in most points (absence of horns, smooth brain, retention of gall-bladder, etc.) has ceased to progress with the rest of the group, while in some few (musk gland, mobile feet) it has taken a special line of advance of its own."
The musk itself, which gives its name to the creature, is found in a gland on the belly, about the size of a hen's egg. The whole gland is cut out and sold in this condition. Such quantities of musk deer have been and are killed for this purpose that the rarity of the animal is increasing. In the seventeenth century it was so common that the traveller Tavernier purchased 7673 musk "pods" in one journey, or, according to Buffon, 1663. The tusks, which recall those of Hydropotes, to which Moschus is not nearly allied, and of Tragulus, with which it has of course still less connexion, are said to be used for the digging up of roots. Its feet, in relation to its mountain-ranging habits, are very mobile.
Extinct Species of Deer.—It has been already mentioned that the most primitive kinds of Deer had no horns at all, resembling in this the modern Moschus and Hydropotes, and that with lapse of time went hand in hand an increasing complexity of antler; the facts of palaeontology harmonising in the most striking manner with the facts of individual development from year to year. The oldest forms seem to be more nearly akin to the living Muntjacs, and their remains occur in the lowest Miocene beds of both Europe and America. At present the group is confined to the warmer parts of Asia and some of the islands belonging to that continent.
One of the oldest types is Amphitragulus. This genus, which consists of several species, inhabited Europe, and differed from living Muntjacs in being totally hornless in both sexes; the skull had no lachrymal fossa or deficient lateral ossification.
Nearly allied is Dremotherium of similar age and range.
The Middle Miocene has furnished the remains of the genus Dicroceras. This is the earliest Deer in which horns have been found. The horns are, as the name of the genus implies, bifid, and have, like those of the living Muntjac, a very long pedicel. This is also a European genus like the last. From this period we come across true Deer, which commence in the Upper Miocene and have branched horns. Moreover they belong, at least for the most part, to the existing genera. One of the most remarkable forms is Cervus sedgwicki (sometimes placed in a separate genus, Polycladus) from the Forest Bed of Norfolk and from the Upper Pliocene of the Val d'Arno. This creature was remarkable for its multitudinously-branched antlers. These end in no less than twelve points. No Deer exists or has existed in which the horns are so completely branched. They are like those of a Red Deer exaggerated.
Fam. 7. Giraffidae.—Undoubtedly the type of a distinct family, Giraffidae, is the genus Giraffa. It is characterised by the long neck, which, nevertheless, consists of only the normal seven vertebrae, and by the "horns" which differ from those of all other Ruminants; they are small bony prominences of the frontal
Fig. 159.—Giraffe. Giraffa camelopardalis. × 1⁄40.
bones, which become fused with the skull, and which are covered with unmodified skin. They are not shed. Between them is a median prominence. This cranial armature is present in the female as well as in the male, and is well developed even in the new-born young. The orbits are completely encircled by bone, and there is no lachrymal fossa, so common in Deer and Antelopes. There are no canines above; but these are present in the lower jaw. The rudimentary digits of other Ruminants have disappeared in this genus. There are fourteen pairs of ribs as in many other Artiodactyla. The liver of the Giraffe is, as in many, but not all, Ruminants, devoid of a gall-bladder; neither has it a caudate or a Spigelian lobe. The caecum is actually largish (2½ feet in length), but is relatively very small, as the small and the large intestines measure 196 and 75 feet in length respectively. The Giraffe has a well-marked "ileo-caecal" gland, found in many Ruminants; its appearance in Giraffa is especially compared by Garrod with its appearance in Alces.
Considered by itself, Giraffa forms a very isolated type of Ruminant. But after we have dealt with certain facts concerning extinct forms clearly allied to Giraffa, the isolation of the family will be found to be less marked.
The Giraffe ("one who walks swiftly," the word means in Arabic) is, as every one knows, limited in its range to the African continent. It is not, however, so familiar a fact that there are two quite distinct species of Giraffe, one a northern form from Somaliland, and the other South African. The distinctness of these two, G. camelopardalis and G. australis, has been lately worked out in some detail by Mr. de Winton. The principal point of difference between them consists in the large size of the median horn in the Cape species, which is represented by the merest excrescence in the other species. The Giraffe of West Africa is held to differ from the northern and southern species, coming nearer to the former. It appears in the first place to be a larger animal, and slight differences in the skull have been pointed out. This series of peculiarities may be expressed, for those who do not object to trinomial nomenclature, by calling this novel western form Giraffa camelopardalis peralta. The existence of the three horns covered with unaltered skin is the main characteristic of this Ungulate. But the Giraffe also differs from other Artiodactyles by its enormously long neck, which enables it to browse upon trees inaccessible to the common herd of Ruminants. The neck is often supposed to have some relation to this method of feeding. But a more ingenious explanation of its inordinate length is that it serves as a watch-tower. The long grass of the districts inhabited by the animal swarms with Lions and Leopards, which must be foes. The long neck allows of a wide look out being kept, and it is noteworthy that the Ostrich, living under similar conditions, is also renowned for its length of neck. It is the spots upon the Giraffe which have given it its name of Cameleopard; these spots present in the southern form a series of chocolate-coloured areas, sharply marked off by white spaces. Of these spots it is asserted that they serve as a means of concealing their possessor. Sir Samuel Baker wrote of it in the following words: "The red-barked mimosa, which is its favourite food, seldom grows higher than 14 or 15 feet. Many woods are almost entirely composed of these trees, upon the flat heads of which the giraffe can feed when looking downwards. I have frequently been mistaken when remarking some particular dead tree-stem at a distance that appeared like a decayed relic of the forest, until upon nearer approach I have been struck by the peculiar inclination of the trunk; suddenly it has started into movement and disappeared."
The Giraffe, remarked Pliny, "is as quiet as a sheep." The Roman public, to whom the first Giraffe ever brought into Europe was exhibited, expected from its name "to find in it a combination of the size of the camel and the ferocity of a panther." As a matter of fact, Giraffes in captivity are not always sheep-like in temper. They will kick with viciousness and vigour, and will even initiate an attack upon their keeper. At the same time they are singularly nervous creatures, and have been known to die from a shock. In moving, the Giraffe uses the fore- and hind-limb of each side simultaneously; this gives to its gait a peculiar rocking motion, the singularity of which is heightened by the curving movements of the long neck, which even describes now and then a figure of eight in the air. Giraffa camelopardalis and the species (?) already referred to are the only existing Giraffes (of the genus Giraffa), and they are not found out of Africa. Sir Harry Johnston has lately given a brief account of a larger and more brilliantly coloured species from Uganda which will probably prove to belong to a distinct genus. It has five horns, the additional pair being placed above the ears.
Sir Harry Johnston has quite recently made known another genus of Giraffidae living in the Semliki forest, Belgian Congo district. The skin and two skulls, as well as the bones of the feet, are known from specimens sent by Sir Harry Johnston to the Natural History Museum, and briefly described to the Zoological Society by Professor Ray Lankester. This creature, of which the native name is "Okapi," is proposed to be called Ocapia johnstoni. The first actual specimens which reached this country were two bandoliers made from the skin of the flanks, which were striped black and white, and were not unnaturally held to be portions of the skin of a new species of Zebra. The animal is of about the size of a Sable Antelope, and the back and sides are of a rich brown colour; it is only the fore- and hind-limbs which are striped, the striping being longitudinal, i.e. parallel with the long axis of the body. The head is Giraffe-like, but there are no external horns; wisps of curled hairs seem to represent the vestiges of the horns of other Giraffes. The tail is rather short, and the neck is rather thick and short. The skull is clearly Giraffine. The basicranial axis is straight, and the fontanelle in the lachrymal region is very large. Upon the frontal bones near their parietal border is a large boss on either side, which presumably represents the horn core or "os cornu." On the mandible the great length of the diastema between the incisors and premolars is a Giraffine characteristic. The Okapi lives in pairs in the deepest recesses of the forest.
We are acquainted with a few extinct forms, belonging to Giraffa, which are extra-African in range. G. sivalensis is from the Pliocene of the Siwalik Hills in India, G. attica from Greece. These remains, however, do not include the top of the skull, so that it is doubtful whether their horns were as in G. camelopardalis.
A closely-allied genus is the extinct Samotherium. This flourished in Miocene times, and its remains have been found in the Greek island of Samos. The neck and limbs are shorter than in the Giraffe, and the horns, longer than in Giraffa, are placed just above the orbit upon the frontal bones alone, instead of upon the boundary line of frontals and parietals as in Giraffa. In several ways, therefore, the existing Giraffe is a more modified or specialised animal than its forerunner of the Miocene. In the latter, the male alone carried horns, and in neither sex does the unpaired median bony excrescence appear. The remains of this genus (probably even the same species, S. boissieri) also occur in Persia.
Helladotherium (there is but one species, H. duvernoyi) has its four limbs of nearly the same length; the skull of the only known example is hornless; the neck is shorter than in Giraffa. It is known from the Miocene deposits of Pikermi in Greece.
Palaeotragus is a genus which is not referred to the Giraffidae by all systematists. Its very name, given to it by the eminent French palaeontologist M. Gaudry, indicates his opinion as to its Antelopine affinities. The chief and indeed (according to Forsyth Major) the only reason for placing this Ruminant with the Antelopes is the large size of the horns. They undoubtedly suggest the horn cores of Antelopes. But they are placed wider apart than in those animals. It is thought that the hornless Camelopardalis parva is the female of this species, which is from Pikermi.
Rather more different from Giraffa is the extinct genus Sivatherium, from the Siwalik deposits of India. Here again there has been some discussion as to its affinities. Some place it in the neighbourhood of Antilocapra, but most palaeontologists now regard it as a Giraffe. The main peculiarity of this large beast was the existence of two pairs of horn cores; the larger are upon the parietal bones, and are of a palmated form, with a few short tines, which are highly suggestive of those of the Elk (Alces). The shorter anterior pair are upon the frontal bones. The neck is short, the limbs of equal length, and there are no additional toes upon the limbs. Sivatherium was almost as large as an Elephant, and in restorations it is depicted as having a fleshy dilated nose like the Saiga Antelope; this view is based upon the position and size of the nasal bones. Hornless skulls have been identified as the female of Sivatherium.
Vishnutherium, Hydraspotherium, and Bramatherium are allied genera.
Fam. 8. Antilocapridae.—This family contains but one genus and species, the N. American "Pronghorn," Antilocapra americana. This animal deserves a family to itself on account of the singular structure of the horns, which are intermediate in character between those of the Deer and those of the Antelopes. They are unquestionably "hollow-horned" Ruminants, in that there is an osseous horn core, upon which lies the actual horn. This, however, is softer than in Bovidae, and is semicorneous. It is, indeed, more like the velvet of the stag's horn. Moreover the horn is branched, and there are sometimes even three prongs. Furthermore, it is now certainly known that the Pronghorn sheds its horns not merely occasionally, but with definite annual periodicity. It so far resembles the Deer. But it must be borne in mind that in the Deer the horn shedding is a twofold process. There is first of all the stripping off of the velvet, and secondly the shedding of a portion of the horn core down to the burr. What happens in the Prongbuck is the shedding of the true horn only ( = the shedding of the velvet), not of the horn core. It appears, however, that occasionally (once in their lifetime?) certain undoubted Antelopes may cast their horns. Another external character of this animal is the total absence of "false hoofs," the last vestiges of the second and fifth digits. The Pronghorn is a gregarious creature running in bands of six up to hundreds.
Fam. 9. Bovidae.—This family, more extensive than that of the Cervidae, contains not only the Oxen, Sheep, and Goats, but also the Antelopes, save only Antilocapra, which must be placed in a family by itself. The only two points which distinguish all Bovidae from all Cervidae are the nature of the horns already described, and the polycotyledonary condition of the placenta. Moreover the horns are usually present in both sexes, though there are exceptions, such as the Sheep and Goats, and various genera of Antelopes (Tragelaphus, Tetraceros, etc.). There are never the first two phalanges belonging to the rudimentary digits II., V., as there are in all Deer excepting Cervulus. There is as a rule but one orifice to the lachrymal duct. There are never persistent upper canine teeth in either sex.
It is exceedingly difficult to separate the Antelopes from the Sheep, Oxen, and Goats. Their inclusion along with these creatures in one family, Bovidae, shows that no differences of an important character exist. The term Antelope is rather of popular than of zoological significance. As a rule there are horns in both sexes; but this rule is not without exceptions, of which one is the genus Strepsiceros, the Koodoo. Many other Bovidae are horned in the males only, e.g. Saiga, Tragelaphus. The Antelopes further differ from the true Oxen in their more graceful build, and in the fact that the horns, if they curve at all, generally curve backwards towards the neck. In the Oxen, on the other hand, the build is stouter, and the horns usually curve outwards. The same remarks apply to the Sheep. Such an Antelope, however, as the Eland (Orias) is very Ox-like in habit. Another feature which may be remarked upon, though not of absolute differential value, is that while the Antelopes are as a rule smooth and sleek in their skins, the Oxen tend to be rough and shaggy. The Zebu, however, in this, in its hump, and in general aspect, is far from being unlike an Eland. But then the Zebu is a domestic race, and we do not know what the wild stock was like. It is perhaps with the Goats that the Antelopes have the nearest affinities, and it is difficult to place such a form as Nemorrhaedus, and indeed some others. In the Antelopes as a rule the middle lower incisors are larger than the lateral ones; in the Sheep and Goats they are alike in size. The parietal bones, too, in the Antelopes are moderately large and are much shortened in the remaining Cavicornia, especially in the Oxen. As the Antelopes are the oldest, so far as we know, of all bovine animals, one would expect to find them combining the characters of the rest. But they do this so effectually that a disentanglement is really impossible. They date from the Miocene. Antelopes are now limited to Europe, Asia, and Africa; they have always had the same range, though more abundant in former times in Europe. They preponderate now in tropical Africa, and abound in genera and species. Messrs. Sclater and Thomas allow altogether thirty-five genera, of which twenty-four are exclusively Ethiopian in range.
In the following summary of the group Messrs. Sclater and Thomas's work is followed. They commence with a section or sub-family of which the type is the Hartebeest.
Bubalis, or Alcelaphus as it is sometimes called, is an African genus, ranging however into Arabia. These Antelopes are characterised by the long skull and the doubly-curved horns. There are eight species of the genus, of which B. caama is the best known; this is the animal known as the Hartebeest. The Bontebok and Blessbok belong to a closely-allied genus, Damaliscus, distinguished mainly by the fact that the bony base of the horn cores is not extended upwards, and therefore the parietal bones are visible when the skull is viewed from in front, which is not the case in Bubalis.
Fig. 160.—Brindled Gnu. Connochaetes taurinus. × 1⁄20.
The Gnus, Connochaetes, are familiar owing to their curious aspect. The hairy face, and rump and tail like those of a pony are highly characteristic. The horns are bovine in appearance, standing outwards and then curving upwards. There are three species of Gnu, all from South Africa. They are C. gnu, C. taurinus, and C. albogulatus.
Of the Cephalophine section there are two genera:—
Cephalophus is an African genus. These animals are known as Duikerboks; they are small, and have short non-curved horns in the male sex only. Their general aspect is not unlike that of certain Deer with simple horns, such as Cervulus. Messrs. Sclater and Thomas allow thirty-eight species. The smallest species do not exceed the dimensions of a Hare. None are really large.
Tetraceros is an Indian genus characterised, as its name denotes, by the fact that it possesses four horns. It is the posterior pair which correspond to the single pair of Cephalophus. The anterior pair, which are much smaller and are sometimes absent, are a new pair. The female of this Antelope is hornless. Sheep are occasionally four-horned, and there is indeed a breed of such in Kashmir. A four-horned Chamois was described by the late Mr. Alston.
The Klipspringer, Oreotragus saltator, is the first type of a third section; as its name denotes, it is an Antelope with Goat-like habits, being found particularly among rocks. The horns are short and straight. This, the only species of the genus, is African in range, of which its Dutch name gives evidence. A specimen in the Zoological Society's Gardens (as has been pointed out to me by Mr. Mercer) had the habit of depositing the secretion of the tear gland upon a mass of concrete in its enclosure, the secretion thus exuded forming a pointed heap of hardish matter. It may be that the object of this is to guide its fellows to its whereabouts.
Ourebia is a less-known genus, larger in size, but with horns of the same character, though longer.
The Grysbok and the Steinbok, genus Raphiceros, have similar horns. This as well as the last two genera have horns in the male only.
One of the smallest of Antelopes belongs to an allied genus; this is Neotragus pygmaeus. It is known as the Royal Antelope, a name apparently derived from Bosman's statement that the negroes called it "the king of the harts." Its horns are very small. The height of the animal is only 10 inches. Horns are present in the male alone. The last three genera are African.
The Cervicaprine series, which is also African, includes the Waterbucks and Reedbucks, so called on account of their water-loving propensities. As in the last series, from which they are separated by Sclater and Thomas, but with which they are united by Flower, there are horns in the male only. These horns, though not twisted, are long. The typical genus is Cobus, of which there are eleven species. The Waterbuck, C. ellipsiprymnus, and the Sing-sing, C. unctuosus, are perhaps the best-known species; the former is blackish grey, the latter browner in colour. In C. maria and one or two other species the horns are more curved backwards and again forwards than in some of the others, where their form is sublyrate.
The Reedbucks, Cervicapra, are closely allied to Cobus; they are, however, of smaller size. Here, as in that genus, the females are hornless, and the horns of the males are of medium size. Five species are referred to the genus. They are all of a brownish fawn colour. A genus Pelea, with but one species, P. capreolus, has been separated on account of the fact that the horns are nearly straight and that there is no naked patch of skin beneath the ears. This animal has received its name on account of its resemblance to the Roebuck.
The Antilopine section includes a number of genera.
The genus Antilope is Indian in range. It includes but one species, A. cervicapra. This Antelope is of medium size, with a brown pelage getting blacker with years; it is thus known as the Black-buck. The female, which is hornless, is lighter brown. The horns are long, spirally twisted, and closely ringed.
Aepyceros, with two species, is African. The Palla (Ae. melampus) is a large Antelope, with longish lyrate horns in the male, which are half-ringed.
The Saiga Antelope, genus Saiga, is one of the most remarkable types of Antelope in its outward appearance. Its nose is very large and inflated, the two nostrils being quite widely separated, a depression indeed lying between them dorsally. The horns are lyrate in the male, absent in the female. The "ovine expression" of this bovine animal is more pronounced in the female. Corresponding with the clumsy nose are very short nostrils, the commencement of the narial aperture being therefore very far back. It is almost suggestive of Macrauchenia in this respect. The fleece is also Sheep-like. The genus occurred in this country during the Pleistocene. It is now an inhabitant of Eastern Europe and Western Asia. The only species is S. tartarica.
The Chiru, Pantholops, is allied to the Saiga. The horns of the male are long and nearly straight; they are ringed in front. The muzzle is swollen in the male; the nostrils are large, and provided with extensive sacs internally. The colour of this animal, which is exclusively Thibetan in range, is a pale fawn. The hair, in accord with its habitat, is very woolly. No living specimens have ever been brought to Europe. This creature has accumulated much legend. Its blood is believed by the Mongols to possess virtues, and by means of the rings on the horns fortunes are told. Naturally the animal is on these grounds hard to stalk and shoot.
Fig. 161.—Loder's Gazelle. Gazella loderi. × 1⁄10.
The Gazelles, genus Gazella, are fairly numerous in species, which are both Palaearctic and Ethiopian. There are altogether twenty-five of them. The genus as a whole is characterised by the small or moderate size, the sandy coloration with white belly, the presence of dark and light stripes on the face and on the flanks. These streaks, however, are not always present, and their presence or absence serves to differentiate some of the species. The horns are usually present in both sexes. The horns are of fair length, ringed, and of lyrate form.
The Springbok is separated from the rest of the Gazelles, to which genus it is clearly most nearly related, as a genus Antidorcas. This genus differs from Gazella by having only two lower premolars as in Saiga. Otherwise it resembles the Gazelles; there is but a single species, A. euchore, which is African.
Ammodorcas is closely allied to the Gazelles, but differs from them in having an elongated neck and also a long tail. A. clarkei, the only species, is limited to Somaliland.
Lithocranius, not unlike the last, has a still longer neck, which makes it almost Giraffe-like; its tail, however, is short. The scientific name is derived from the "solid stony character of the cranium." In running, this Gazelle carries the head forward in a straight line with the body. It is African.
Dorcotragus with one species, D. megalotis, is a pigmy Gazelle restricted to Somaliland. Its likeness, on account of size and in some other superficial features, to the Klipspringer, led to its original confusion with that genus (Oreotragus).
Fig. 162.—Sable Antelope. Hippotragus niger. × 1⁄20. The horns of the specimen figured have not nearly reached their full dimensions.
A sub-family Hippotraginae, or Hippotragine section, includes a number of Antelopes which agree in the possession of four mammae, and of molars more like those of the true Oxen, of horns of some length, present in both sexes, and of a longish tail. They are all African in range.
The type genus Hippotragus has its horns placed above the orbits; they are not twisted, but curved backwards. There are three species in the genus. Of these the best known is H. niger, the beautiful Sable Antelope. Its general colour is a rich, dark, glossy brown with white stripes on the face, and with a white belly. The other species are the Roan Antelope, H. equinus, and the Blaaubok, H. leucophaeus, of which the last specimen was probably killed in 1799.
Fig. 163.—Beatrix Antelope. Oryx beatrix. × 1⁄16. (From Nature.)
The genus Oryx (chiefly African, but also Arabian and Syrian) also contains a number of species, which are fairly familiar through the fact that several of them are always on view in the Zoological Society's Gardens. The genus differs from Hippotragus in that the horns, present in both sexes, are placed behind the orbits, and slant backwards in a line with the face. They are annulated. The Leucoryx (O. leucoryx) is of a pale colour, but this is not so marked as in O. beatrix, which is largely white with, however, brown legs. The Gemsbok is a handsome creature with greyish tawny colour, much darker on the legs, and with a Gazelle-like, dark, side stripe. It has received its vernacular name on account of its supposed likeness to the Chamois ("Gemse"), just as the Rehbok was so-called from its supposed likeness to the Roe Deer, and the Eland to the Elk. The Beisa (O. beisa) is of a similar tawny colour to the last, and also with darker stripes.
The Addax (Addax) of North Africa, Arabia and Syria, has but one species (A. nasomaculatus). The horns are spirally twisted.
Fig. 164.—Speke's Antelope. Tragelaphus spekii (♀). × 1⁄16.
The Tragelaphine section includes the Kudus, Elands, Nilgais, and Harnessed Antelopes. They are all long-horned (when the horns are present in both sexes), the horns being twisted; the nose is naked with a slight median groove, and all are Ethiopian or Oriental in range.
The genus Tragelaphus includes the Harnessed Antelopes, so called on account of the direction of the stripes suggesting harness. The females are hornless, and the colours of the two sexes are different. The hoofs are long and the toes rather unusually separable, which state of affairs is in accord with the swampy country affected by many. T. gratus and T. spekei are larger forms; the Boschbok, T. sylvaticus, is smaller.
The Kudus, genus Strepsiceros, have more markedly twisted horns, which are absent in the female. The body is vertically striped with white. The largest species is S. kudu; a smaller form, S. imberbis, is from Somaliland.
Fig. 165.—Eland. Orias canna. × 1⁄25.
The last genus of this section or sub-family is the African Eland, genus Oreas (which it appears should be spelt Orias). The Elands are perhaps more Ox-like in appearance than the other members of this group, and in both sexes have horns, in which the spiral twisting is more close. Orias canna is the name of the common Eland. O. livingstonii has been applied to an East African variety, which has thin and faint lateral stripes like the other members of the group to which it belongs.
The genus Boselaphus includes only B. tragocamelus, the Nilgai, which is purely Indian in range. The female is hornless, and the horns of the male are smooth and not long.
The members of the Bovine section or Oxen are to be distinguished from other hollow-horned Ruminants by their stouter build and by the fact that the horns stand out from the sides of the skull and are simply curved, not twisted; and smooth, not annulate like those of other Ruminants. The muffle is naked, broad, and moist. The Oxen are widely distributed; but are entirely absent from the Australian region and from South America and Madagascar.
The true Oxen are perhaps best considered to form but a single genus, Bos. They have, however, been divided into a number of genera. Even the supposed aberrant Anoa depressicornis of Celebes hardly differs sufficiently to warrant its separation. In favour of this view, too, is the extraordinary ease with which different "genera" will cross with each other and produce fertile offspring. The following is the pedigree of an animal lately living in the Zoological Society's Gardens. The female offspring of a male Zebu and a female Gayal was mated with a male Bison. The female calf was again mated with a Bison and produced a calf, also a female, which contained therefore the three species, Bos indicus, Bibos frontalis, and Bison americanus. It is clearly unwise in view of this fact to insist too much upon generic distinctions in any of those types.
Of this genus the Oriental Gaur (Bos gaurus), the Gayal (B. frontalis), and the Banteng (B. sondaicus) form a well-marked section, characterised by their dark coloration and by the somewhat flattened horns.
The Gaur, Bos gaurus, has a more concave forehead than its allies; the horns are less curved than those of the Banteng, and less so than the horns of the Gayal (Bos frontalis). It inhabits the Indian Peninsula; and extends through Burmah to the extremity of the Malay Peninsula. The Malay name of this animal is Sakiutan, which simply means wild cattle. It chiefly frequents wooded hills and is an excellent mountain climber.
Bos frontalis, the Indian Gayal, has a white caudal disc like the last species, but the forehead is flat and the horns curve but little. It is chiefly known as a tame animal, and its occurrence in the wild state has been doubted. It has furthermore been suggested that it is merely a tame race of the Gaur altered slightly through domestication. It is, however, said not to cross in a state of nature with the Gaur.
Fig. 166.—Gayal. Bos frontalis. × 1⁄20.
The Banteng, B. sondaicus, is distributed through Chittagong, Tenasserim, and the Malay Peninsula to Java and Borneo. There are apparently two races of this animal. The species differs from the others by the fact that the horns are smaller and more curved; there is a white caudal disc; the forehead is narrower and the skull longer than in the others.
The American Bison and the European Aurochs form another section; they are indeed extremely alike, specific differences being hardly recognisable. The Bison of America, formerly present in such numbers that the prairies were black with countless herds, has now diminished to about a thousand head.
One of the largest of existing Bovidae is the Aurochs, Wisent, or European Bison, Bos bonasus (or Bison europaeus). It is exceedingly like its American relative. Formerly the animal was much more widely spread than it is now, extending its range from Europe into North America. It is now limited to certain districts on the Urals, in the Caucasus, and a herd of them are kept up through the fostering care of the Emperor of Russia in the forest of Bielovege in Lithuania. The term "Aurochs" should not really be applied to this species but to the Wild Cattle, Bos taurus. It is, however, so generally used for the Wisent (which is the German name) that it is not necessary to change it. The Sclavonic name is Zubr or Suber. It is a great beast, standing 6 feet or so in height at the shoulder. It ranged further over Europe well within the historic period. In the days of Charlemagne it was spread over Germany and was a beast of the chase. In the year 1848 the Emperor of Russia presented a pair of these Oxen to the Zoological Society of London. At the time of their presentation an interesting communication was made to the Society by M. Dolmatoff, on the method of the capture of these two examples. The creature is not easy to capture and is alarming to confront. "The eyes," says an old writer, "are red and fiery; the looks are furious and commanding." It has of course the shaggy mane and hump of the American animal. The herd in Lithuania was said to be 1900 in the year 1856. Mr. E. N. Buxton, who has lately visited the forest, quotes M. Neverli to the effect that at present the numbers are not more than 700.
Fig. 167.—Bison. Bison americanus. × 1⁄25.
Allied to this animal, and apparently still nearer to the American Bison, is the extinct B. priscus of Europe. The Pleistocene Bisons of North America, B. antiquus and B. latifrons, are not remote from the living forms. Finally, the Miocene B. sivalensis from India, and the Pliocene B. ferox and B. alleni of North America, take back this group to as remote a period as any other genus of Oxen.
Fig. 168.—Yak. Bos grunniens. × 1⁄15.
Fig. 169.—British Wild Ox. Bos taurus. From Vaynol Park, Bangor. × 1⁄20.
The Yak, Bos grunniens, is a long-haired peculiar type, confined to the Thibetan plateau. B. (Anoa) depressicornis of Celebes is characterised by its straight horns; allied to it is B. mindorensis (Philippine Islands), supposed, however, to be a hybrid between it and some other species. Africa has at least two Buffaloes. We may finally mention the Wild Ox of Europe, B. primigenius, the supposed progenitor of our domestic cattle, believed to be still surviving in the herds at Chillingham, Chartley, and elsewhere. This animal is sometimes called the Aurochs. The Romans spoke of it as the Urus, and it appears to have formerly attained to more gigantic proportions than at present. It is the small size of the present race that is the chief objection to tracing them back to the large Oxen existing near London in 1174, and found sub-fossil in the Cambridgeshire fens.
Fig. 170.—Punjab Wild Sheep. Ovis vignei. × 1⁄10.
Of the true sheep, genus Ovis, there are a considerable number of species. The Sheep are to be distinguished from the Goats by their rather stouter build and by the absence of the beard in the male. The horns are developed in both sexes, and are usually twisted and often of large size.
The Sheep are almost entirely Palaearctic and Nearctic. They only just get into the Oriental region. One of the finest species is the great Pamir Sheep, O. poli, whose length reaches 6 feet 7 inches, and height 3 feet 10 inches. The horns of this fine Sheep may measure more than five feet round the curves. The Rocky Mountain Bighorn (O. montana) is a Sheep ranging along the Rockies as far south as New Mexico, and also to the far north; they are not confined to the chain of mountains mentioned, but occur also on the mountains of British Columbia down to those of California. The horns are not quite as large as those of the last species, but measurements give a length (along the curve) of 32 to 40 inches.
Fig. 171.—Himalayan Burrhel Sheep. Ovis burrhel. × 1⁄12. (From Nature.)
Just as the Goats are often limited to islands and small stretches of country, so are the Sheep. Thus Cyprus has a species, O. ophion, peculiar to itself. This, which is known as the Cyprus Mouflon, is limited to a range of mountains, the Troodos, in that island. In 1878 it was believed that the animal was nearly exterminated, a flock of twenty-five members alone surviving. They have, however, since increased. Confined
Fig. 172.—Blanford's Sheep. Ovis blanfordi. × 1⁄10. (From Nature.)
Fig. 173.—Barbary Sheep. Ovis tragelaphus. × 1⁄10.
Fig. 174.—Thar. Capra jemlaica. × 1⁄10. (From Nature.)
Ovis nahura is chiefly responsible for the impossibility of strictly separating the Sheep and Goats. It has no suborbital glands or lachrymal fossae, which are as a rule present in the Sheep and absent from the Goats. On the other hand interdigital glands are present, which is the case with Sheep. Its habits, too, are a blending of those of the Sheep and the Goat. It lives largely on undulating ground like Sheep, and frequently lies down during the day on its feeding ground. On the other hand it is, like the Goats, a splendid climber.
The Goats, genus Capra, differ from the Sheep in their slighter build and in the fact that the horns are not spirally curved, but arched over the back. There is also the characteristic beard, and the male is odorous. The true Goats are almost exclusively Palaearctic in range. They show the limited distribution of the Sheep, a distribution which follows from their mountain-loving habits.
Fig. 175.—Sinaitic Ibex. Capra sinaitica. × 1⁄10.
Thus we have the Spanish Ibex (C. pyrenaica), limited to the Pyrenees and other mountain ranges of the peninsula; C. ibex, the Steinbok of the Alps and the Tyrol; the Markhoor, C. falconeri, of certain mountain ranges of Afghanistan; the Caucasian, Sinaitic, and Cretan Ibexes, and the Thar.
Capra aegagrus, the Persian Wild Goat, ranges from the Caucasus to Sind. It is this animal which produces the true "bezoar stone." The substance in question is a secretion apparently found in the stomach. It is still, according to Mr. Blanford, regarded as an antidote to poison in Persia. Buffon called this Goat the "Pasan," which is evidently a corruption of the word bezoar. When the substance was in repute as a medicine of the "alexipharmic" kind, the supply naturally came up to the demand. Thus the bezoar stones of the Lama in South America gained repute, and there were "Oriental bezoar, cow bezoar, hog bezoar, and monkey bezoar"! As concretions of one kind or another are not uncommon objects in the alimentary tract of mammals it was easy enough to obtain a fair amount of some substance which was sure to sell well. It is said that a stone weighing four ounces was once sold in this country (or at any rate in Europe) for £200.
"There can be no doubt," observes Mr. Blanford, "that C. aegagrus is one of the species, and probably the principal, from which tame goats are derived."
Fig. 176.—Japanese Goat Antelope. Nemorrhaedus crispus. × 1⁄12. (From Nature.)
The Chamois (Rupricapra) and the Goral (Nemorrhaedus) are best described as Goat-like Antelopes; but, as already said, it is difficult to split up the Bovidae satisfactorily. The Rocky Mountain Goat, Haploceros montanus, is a large Goat-like creature, which has the peculiarity of having the shortest cannon bones of any Ruminant. Its name denotes its range.
Fig. 177.—Goral. Nemorrhaedus goral. × 1⁄12. (From Nature.)
The Musk Ox, Ovibos moschatus, has been thought to be on the borderland between the Sheep and Oxen, as indeed expressed in its scientific name. It is a purely Arctic creature, now confined to the Nearctic region; but it formerly existed in the Arctic regions of Europe.
The anatomy of the "soft parts" of this genus has lately been investigated by Dr. Lönnberg. The animal has no foot glands such as occur in Ovis. Its kidneys, however, are non-lobate, and it has orbital glands. The cotyledons of the placenta are unusually large, and the cow has the "primary four" teats. It cannot, in fact, be definitely referred to either the Caprine or the Bovine section of the Cavicornia, and while possibly most allied to Budorcas, it may be regarded, at least for the present, as entitled to form a separate sub-family of its own. The muzzle has a slight naked strip above the nostrils, as in the Sheep, but there is no fissure of the upper lip.
Extinct Families of Artiodactyla.
The origin of the Artiodactyla is placed by Cope in the family Pantolestidae, allied to the genus Protogonodon of the Condylarthra. As, however, this family is represented by but a few back teeth and a fragment of the hind-foot, it seems premature to regard it as the necessary starting-point of the Bunodont and Ruminant groups.
Fam. Anthracotheriidae.—This well-known and ancient family consists of creatures of for the most part a Pig-like form, with teeth approaching the selenodont shape, and a complete dentition. The carpals, tarsals, metacarpals, and metatarsals are all free. The toes are four (or five) to each foot, with the outermost beginning to be reduced. These of course are all generalised and primitive characters, pointing nowhere in particular, except, of course, to an Artiodactyle stock, on account of the teeth and the two predominating toes.
The type genus of the family, Anthracotherium, is not, as its name might seem to denote, a relic of the Carboniferous period; its remains were found in lignite, which may also show that it was at least semi-aquatic in habit. Its form, however, must have been Pig-like, so at least one would presume from the elongated skull and shortish legs. There were species as great as a Rhinoceros, and smaller forms. The genus began in the Oligocene and continued down to the Pliocene. It is known from Europe, Asia, and America.
The skull is long with a prominent sagittal crest. The facial part is also very long, and the orbits are not closed by a bony ring. The premolars are simple teeth; the molars distinctly bunodont with a tendency in one or two to the selenodont condition. The canines are powerful, as are also the incisors. The scapula has been specially compared with that of the Camel. It has no acromion, which is usually though not always absent in Ungulates. An ally of the present animal, for instance, the Hippopotamus, has the acromion developed. The radius and ulna, the tibia and fibula, are all fully developed.
Ancodus (or Hyopotamus, as it has been called) is also Oligocene in range, and its remains have been found in the same countries as have those of Anthracotherium. Both genera are indeed closely allied. Ancodus seems to be a more slightly-built creature. The skull looks weaker, but presents much the same features of organisation. In A. velaunus, a species found in French rocks, a metacarpal of digit I. was present in the manus, while A. brachyrhynchus had a completely five-fingered manus.
The Miocene genus Merycopotamus (from the lower layers of the Siwalik formation in India) is more distinctly selenodont than the forms already discussed. On this ground it has been placed in a separate sub-family. As, however, in other respects it does not depart from the Anthracotherian type of structure, this proceeding seems to be hardly necessary. There are two species known, of which one, M. nanus, is, as its name denotes, a dwarf form.
Fam. Caenotheriidae.—While the last family consisted of animals rather more akin to the Pigs, the present is more Pecorine in its characters. The molars are selenodont; but as in the Tragulidae the premolars are more of the nature of cutting teeth. The dentition, like that of so many of these early Ungulates, is complete, and the canines are not prominent. The feet are four-toed, the lateral toes not reaching the ground.
The principal genus is the Eocene and Miocene Caenotherium. Of this genus there were a considerable number of species all European in range, and of small size—not more than a foot or so in length. Their small size is suggestive of the Chevrotains. In the skull the orbital cavity is nearly or quite surrounded by bone, and the tympanic bulla is large and inflated. A common feature of Artiodactyles, a failure of the nasals and maxillae to meet at the side of the face, is to be seen in this ancient forerunner of the Pecora.
Plesiomeryx, also European, and from the same geological horizon, is a very closely allied form.
Fam. Xiphodontidae.—This family consists of slender, small Artiodactyles which are, like the Caenotheriidae, related to the Pecora. They are confined in their range to Europe.
The type genus Xiphodon has selenodont molars and elongated, slender, cutting premolars. The dentition was complete and the canines not highly developed. Like Caenotherium, Xiphodon was a hornless creature, but with only two toes, the two lateral digits being represented by the merest rudiments of metacarpals. The other metacarpals were unusually long.
Amphimeryx (also called Xiphodontotherium) is much more imperfectly known, but belongs to this family or to that of the Caenotheriidae. Dichodon is another member of the same family.
Fam. Oreodontidae.—This family, consisting of numerous genera, is limited to the North American continent. Its range in time is from the Eocene to the Lower Pliocene. The family as a whole is to be distinguished by a number of primitive characters. The dentition is complete; the feet are four- or even five-toed; the orbit is sometimes open behind. The canines of the lower jaw are not more pronounced than the incisors. The characteristics of the group will be further developed by a consideration of some of the principal genera which are included in this family.
Oreodon is a Miocene form about as large as a Peccary. The skull has a short face with a completely-closed orbital cavity. In front of the orbit is a deep pit, not a mere deficiency of ossification, such as occurs in many Artiodactyles. This is placed on the lachrymal bone, and is in fact a lachrymal fossa, such as occurs in other forms. The odontoid process of the axis vertebra is somewhat cheese-taster shaped, as in recent Artiodactyles. There are fourteen dorsal vertebrae and a very large number of caudals. The radius and the ulna are completely separated, as are the carpals. There are five digits to the fore-limbs. The fibula is complete and independent. The hind-foot is four-toed. Several species of the genus are known.
Merycochoerus is an allied Miocene genus. It is more massive in form than the last, but otherwise does not present differences of importance.
Mesoreodon is another genus of this family which presents some curious features of organisation. In the skull and teeth there is nothing very noteworthy, but the hyoid is remarkable. This appendage of the skull is by no means always preserved, and when it is, it might be denied that it belonged to any particular skull. In the present case there appears to be no doubt as to the identity of the bones, which resemble the corresponding bones of the Perissodactyla much more than they do those of other Artiodactyles. Associated with the bones an ossified thyroid cartilage of the larynx was found. As the skull was that of a male, this character may be a sexual one. It is quite comparable to the ossification of the same cartilage in the American monkey Callithrix. "The function of the bone," observes Professor Scott, "was probably similar to that performed by the enormously-inflated basihyal of the howling monkeys, and must have given to these animals most unusual powers of voice." Another important anatomical fact about Mesoreodon is the apparent existence of a clavicle. It is of course conceivable that the remains of some other animal have got mixed up with that of the individuals upon which the present genus is founded; but failing that, here is a clavicle in an Ungulate. The spine of the scapula possesses a metacromion. This greater development of the spine of the scapula in Artiodactyles than in Perissodactyles is, it is suggested, to be correlated with the earlier loss of the clavicle in the latter group of Ungulates.
Cyclopidius (synonymous with Brachymeryx) is a kind of pug form of Oreodon. The skull is short and broad, and the end of the snout a little turned up. The upper incisors are small and drop out early. On each side of the nasals is a large oval vacuity which is perhaps to be compared to the lateral deficiency to be found in other Artiodactyles. One species of this singular-looking form is appropriately called C. simus.
Other allied genera are Merychyus and Leptauchenia. The former extends as far down as the Lower Pliocene, and is thus one of the newest forms of Oreodontidae.
Agriochoerus (Fig. 178) is placed in a separate sub-family from the types which have just been considered. It is Miocene in range. It differs from Oreodon and its closer relatives by the fact that the orbit is open behind and not closed. The most remarkable fact about this creature is that the terminal phalanges of the digits (five in the fore- and four in the hind-feet) being pointed, seem to suggest their encasement with claws rather than hoofs. The pollex, though small, seems to have been opposable. As with other Oreodonts, the molars are selenodont. The premaxillae are toothless—at least in adults, for two teeth are present in the young. There are several species. Agriochoerus, like Oreodon and primitive Ungulates in general, had a long tail. The genus thus shows a mixture of ancient and specialised characters.
Fig. 178.—Skeleton of Agriochoerus latifrons. × ⅛. (After Wortman.)
The most ancient form of Oreodont is Protoreodon. This is Eocene, and became extinct during that period. It had a complete dentition, open orbit, and no lachrymal fossa. The fore-feet were five-toed, the hind four-toed.
Fam. Anoplotheriidae.—This family is entirely Eocene in point of time, and is unknown outside Europe. The dentition of the group is complete; the molars are seleno-bunodont, like those of the Anthracotheriidae. The bones of the carpus, tarsus, metacarpus and metatarsus are all free; the toes are four to two in number on each foot. The orbit is widely open behind. The tail is long, as in Xiphodon, etc.
These general characters only just serve to differentiate the family; but they illustrate its archaic character, in which it resembles the Xiphodontidae, and even more the Anthracotheriidae. A survey of some of the genera which have been assigned to the family will bring out other features in the organisation of these very ancient Artiodactyles.
Anoplotherium is so called on account of the fact that it is, like all ancient Artiodactyles, without horns or claws. Tusks it might have, but as a matter of fact has not. There are, as in Artiodactyles generally, nineteen dorso-lumbar vertebrae; the long tail has numerous chevrons. The shoulder blade has a well-marked acromion and a distinct coracoid process; it is wide proximally. The bones of the fore-arm and fore-leg are, as is usual in primitive Artiodactyles, separate.
In the skull the chief features, in addition to that mentioned in the definition of the family, are the large size of the paroccipital processes; there is no fossa lachrymalis or deficiency in the side of the face. The animal is three-toed, both in the fore- and hind-limbs. The second toe is nearly as large as the Artiodactyle third and fourth. There are tiny rudiments of the two remaining fingers. The hind-foot is also three-toed, and there is a trace of the hallux. The fingers are so widely separated and divergent from each other that it has been suggested that the animal had webbed feet and inhabited marshes, in which it swam by the aid of its long tail. The creature was the size of a Tapir.
Closely resembling Anoplotherium are a number of other genera.
Diplobune ( = Hyracodontotherium) was much like the last, but was a more delicately-formed animal. The fingers and toes (three of each) end in such sharply-pointed phalanges that claws seem to be almost suggested. There are several species of this genus. Dacrytherium differs by the presence of a lachrymal fossa.
Dichobune has four-toed extremities, of which the lateral ones are more slender and shorter than the two middle ones. As in other Anoplotheriidae, the anterior premolars are furnished with a sharp cutting edge.
Order V. SIRENIA.
Aquatic Mammalia, with but few scattered hairs; hind-limbs absent; fore-limbs paddle-shaped; tail flattened, and either Whale-like or rhomboidal to circular in form. Nostrils on upper surface of not specially-elongated snout. Clavicles are absent. The scapula has the normal mammalian form, with a well-developed and roughly median spine. The bones of the arm and hand articulate together, as in land animals; the phalanges show at most traces of increase in number above the normal. Pelvis represented by a vestige, more highly developed in some fossil than in recent forms. Stomach complex, consisting of several chambers. Lungs simple and not lobulated. Diaphragm oblique and very muscular. Brain peculiar in form and but slightly convoluted. Testes abdominal. Teats two, and pectoral in position. Placenta non-deciduous and zonary.
This limited group consists of purely aquatic forms, which are both marine and fresh-water in their proclivities. They have been placed in the immediate vicinity of the Whales; but it is now believed by most zoologists that the likenesses which they undoubtedly show to the Cetacea are of an adaptive kind and related to their similar mode of life. The group is a readily-definable one. Externally they are marked by their dark coloration, somewhat Whale-like though of clumsier build, and by the total absence of external ears and hind-limbs; the latter are, however, as will be pointed out shortly, marked by certain rudimentary bones. There is a flattened tail, which in the Dugong and Rhytina is precisely like that of a Whale. It is interesting to note that the former genus, whose tail is, judging it at least by the standard of the Whales, more completely modified for the aquatic life, should also show other features which indicate their longer life as marine creatures. For the flippers are more Whale-like in that the fore-arm is completely enclosed within the body, or nearly so, and the nostrils have a more decidedly superior position than in the Manatee. The fore-limbs of this group, as may be inferred from what has just been said, are flipper-like; but, contrary to what we find in Whales, the phalanges do not as a rule show any traces of multiplication, so characteristic a feature of the Cetacean hand, and the individual bones are connected by well-formed joints. Beneath the thick skin, which is sparsely provided with stout hairs in the Dugong, is a layer of blubber. Dr. Murie has called attention to the fact that this layer in the Manatee differs from the blubber of the Whale in that there is no free oil anywhere.
The skeleton of the Sirenia is strong and massive, thus contrasting with the loosely-textured bones of the Cetacea. The cervical vertebrae are, as a rule, free, but the second and third are fused in Manatus and the extinct Halitherium. It is noteworthy that in Rhytina the cervical vertebrae have the exceedingly thin centra that characterises the neck vertebrae in Whales. The ribs are most of them firmly articulated by two heads. The breastbone is generally reduced, as in Whales; and but few ribs are attached thereto. The vertebrae, moreover, are well locked together by zygapophyses, and not loosely attached as in Whales.
The shoulder blade is long and narrow, and not unlike that of the Seals. It is totally unlike the peculiarly-modified scapula of the Whale tribe. But, as in the latter, there are no clavicles.
The hind-limbs are only represented by the pelvis; and this is a rudimentary structure, varying, however, in the degree of its degeneration. That of the extinct Halitherium recalls the pelvis of the Rorqual. There is a single triradiate bone with an acetabular cavity for the rudiment of the femur in the centre; it suggests that here the three normal elements of the pelvis have become fused into a single bone. In the Dugong there are two small bones on each side.
The Manatees (Manatus) are found in the fresh-waters and along the Atlantic coasts of South America and Africa. It appears that there are four species, of which one only is African, the others American. Report asserts the former occurrence of this genus on the shores of St. Helena.
The Manatee is provided with only six cervical vertebrae, a fact which distinguishes it from the other existing genera of its group. A remarkable feature which it exhibits is the large number of molar teeth. These apparently go on increasing indefinitely during its life, the suggestion being that they are worn away by the nature of the food—algae with much sand intermixed. As many as twenty molar teeth have been counted in one half of the jaw, and there is no reason to forbid the assumption that they may get still more numerous. This large number of grinding teeth is obviously suggestive of the Whales, with which the Sirenia are believed by some to be allied. It is at least a remarkable coincidence that these two aquatic groups of mammals should both have assumed the same indefinite tooth formula. It is correct to say assumed, since extinct forms of Manatees, such as Halitherium and Prorastoma, have not a continuous succession of molars. The brain of the Manatee is, contrary to the usual arrangement among aquatic mammals, smooth, and only marked by one or two fissures.
The Manatee is black in colour, its thick skin being wrinkled. The animal is assisted in feeding by a curious mechanism of the upper lip; this is split in two, and the two halves, which are furnished with strong bristles, can play upon each other like the points of a pair of forceps. The flippers are furnished with nails, save in M. inunguis, but in the nailed forms it is not every finger which is thus armed.
Fig. 179.—Skeleton of Dugong. Halicore australis. (After de Blainville.)
Halicore, the Dugong, is an entirely Oriental and Australian form; there appears to be but a single species, though more than one name has been given to supposed distinct species. As already mentioned, it differs from the Manatee in the possession of a Whale-like tail; the nostrils, too, are more upon the upper surface of the head, and there are no nails upon the flipper. The peculiar cleft lip of the Manatee is not so well developed in the Dugong, but there are traces of it; and in the foetus the likeness to the Manatee in this respect is very striking. It would thus appear that Halicore is a stage in advance upon Manatus; that the remarkable mechanism of the lip of the latter has been possessed, but has been lost, by the Dugong. The skull of the Dugong is distinguished by the stout premaxillary bones, which bear a tusk in the male. In the female the tooth is there, but is lodged within the bone. This incisor has a milk forerunner. The back teeth of the Dugong (there are no canines) are few in number (four or five, even six), thus showing a gradual reduction when compared with Manatus; and this culminates in the toothless Rhytina. It is also interesting to notice that in the massive lower jaw there are traces of an incisor. Were this to be developed into a tusk, the jaw would present a curious resemblance to that of Dinotherium.
The Dugong, H. dugong, has the reputation of being the original of the mermaid legends, since the young is held to the pectorally-situated breast with one flipper. "But it should be remembered," justly observes Dr. Blanford, "that stories of beings half man or woman, half fish, are as common in temperate as in tropical seas, and that some of them are more ancient than any European knowledge of the Dugong."
Extinct Sirenians.—The earliest genus that can be with certainty referred to this order is the Oligocene Prorastoma. This genus, though offering no particular skull-characters that assist in the determination of the much-debated affinities of the Sirenia, shows a remarkable condition of the teeth that may afford a clue. The species P. veronense, recently described by Mr. Lydekker, is founded upon a fragment of the skull which contains two teeth apparently representing the third and fourth upper milk molars. The interest attaching to these teeth lies in the fact that they clearly exhibit the buno-selenodont condition characteristic of certain early Artiodactyles, e.g. Merycopotamus.
Halitherium is a later genus, which is known by the nearly complete skeleton. The skull is like that of other Sirenia, with the down-turned premaxillary region. But the nasal bones, lost, or at least rudimentary, in recent forms, are well developed; the likeness of ancient to living forms in this respect being exactly paralleled by the Zeuglodonts, when compared with recent Whales. The vertebral centra exhibit distinct epiphyses, which have disappeared in living Sirenians. The cervical vertebrae are seven, of which the second and third are occasionally fused. There are nineteen pairs of ribs, and there are three lumbar vertebrae. The sternum consists of three separate pieces. There is a rudimentary femur.
The recently-extinct Steller's Sea-cow, belonging to the genus Rhytina, was a huge beast, seen in the flesh up to nearly the end of the last century. It frequented the shores of Bering's Straits. Its remains occur in the peat on the shores of those seas. It reaches a length of some 20 to 30 feet. The external characters were much like those of other recent Sirenians. The nostrils were above the fore part of the snout, the latter being truncated and obtuse. The tail was of the Cetacean pattern, and thus like that of Halicore. The head of this Sirenian was small, and the teeth had entirely vanished save for the apparent existence as transitory structures of two small incisors in the upper jaw. The absence of teeth was compensated by the presence of a horny palate for the trituration of the sea-weeds which constituted the food of Steller's Sea-cow. The fore-limbs seem to have possessed no nails, but were covered at the extremity with short, bristly hairs, no doubt serving the purpose of keeping the animal moored in safety to the slippery beds of Fucus upon which it browsed.
There are nineteen pairs of ribs. The vertebrae of the cervical region are the customary seven, and the centra are thin and plate-like as in the Cetacea, the animal being thus short-necked like those marine creatures.
- See Bateson, Materials for the Study of Variation, London, 1894, p. 387.
- See, however, p. 196, for a discussion as to which is the more primitive arrangement.
- Titanotherium (see p. 266) is exceptional.
- Bones of Hippopotamus, however, indicate the very recent occurrence of that animal in Madagascar.
- "On the Pygmy Hippopotamus of Liberia," Proc. Zool. Soc. 1887, p. 612.
- Tomes, Proc. Zool. Soc. 1850, p. 160.
- There is, however, some doubt about the first premolars.
- Dr. Garson has investigated its anatomy, Proc. Zool. Soc. 1883, p. 413, and states that its differences from Sus are "unimportant and few."
- "On the Species of Potamochoerus," Proc. Zool. Soc. 1897, p. 359.
- Marsh, Amer. Journ. Sci. xlvii. 1894, p. 407.
- Osborn, Bull. Amer. Mus. Nat. Hist. vii. 1895, p. 102.
- Marsh, Amer. Journ. Sci. xlviii. 1894, p. 262.
- For the structure of Tragulus, see Milne-Edwards, Ann. Sci. Nat. (5) ii. 1864, p. 49.
- Marsh, Amer. Journ. Sci. 1897, p. 165.
- This is the winter dress. In the summer both camels lose their long rough hair.
- See Wortman, Bull. Amer. Mus. Nat. Hist. x. 1898, p. 93.
- "Osteology of Poebrotherium," Journ. Morph. v. 1891, p. 1.
- Unless Protoceras (see p. 284) was furnished with horns.
- Sir Victor Brooke, "On the Classification of the Cervidae," Proc. Zool. Soc. 1878, p. 883.
- It has been occasionally recorded in an Axis Deer, and in another species, Cariacus superciliaris.
- It is not every one that admits so many genera. I follow Sir Victor Brooke.
- Garrod, "On the Chinese Deer named Lophotragus michianus by Mr. Swinhoe," Proc. Zool. Soc. 1876, p. 757.
- Proc. Zool. Soc. 1877, p. 789.
- Proc. Zool. Soc. 1882, p. 636.
- Sir W. Flower "On the Structure and Affinities of the Musk Deer (Moschus moschiferus)," Proc. Zool. Soc. 1875, p. 159; Garrod, loc. cit. 1877, p. 287; and F. Jeffrey Bell, Proc. Zool. Soc. 1876, p. 182.
- For the viscera, see Garrod, Proc. Zool. Soc. 1877, p. 5, etc.; and ibid. p. 289, etc.
- Proc. Zool. Soc. 1897, p. 273.
- Wild Beasts and their Ways, 1890, p. 151.
- See also Sclater, Proc. Zool. Soc., 1901, ii. p. 3.
- Forsyth Major. Proc. Zool. Soc. 1891, p. 315.
- "On the Shedding of the Horns in the Prongbuck," see Bartlett, Proc. Zool. Soc. 1865, p. 718; Canfield, ibid. 1866, p. 105; Murie, ibid. 1870, p. 334; and Forbes, ibid. 1880, p. 540.
- The distinction between the two families has been called "fanciful." It may be admitted that it is not great.
- The Book of Antelopes, London, Porter, 1894-1900.
- They are straight in the young.
- W. L. Sclater, The Fauna of South Africa, Mammals, i. 1900.
- Taurotragus oryx has unfortunately been discovered to be the correct name for the Eland.
- A. D. Bartlett, "On some Hybrid Bovine Animals bred in the Society's Gardens," Proc. Zool. Soc. 1884, p. 399.
- See Proc. Zool. Soc. 1890, p. 592.
- Proc. Zool. Soc. 1899, p 64.
- Proc. Zool. Soc. 1900, p. 142.
- The name Trigonolestes has to be substituted for Pantolestes.
- Trans. American Phil. Soc. xviii. 1896, p. 125.
- For complete osteology see Wortman, Bull. Amer. Mus. Nat. Hist. vii. 1895, p. 145.
- In Halicore; probably also in Manatus. See Turner, Trans. Roy. Soc. Edinb. xxxv. 1889, p. 641.
- Kükenthal has discovered a thick coating of rudimentary hairs in the foetus of the Manatee, thus showing that it is the descendant of an animal furry like a Seal.
- "On the Manatee," in Trans. Zool. Soc. vol. viii. 1872, p. 127.
- Hartlaub, "Beiträge zur Kenntnis der Manatus-Arten," Zool. Jahrb. 1886, p. 1.
- Beddard, "Notes upon the Anatomy of a Manatee (Manatus inunguis)," Proc. Zool. Soc. 1897, p. 47.
- See Kükenthal in Semon's "Zoolog. Forschungen," Denkschr. Jen. 1897; Langkavel, "Der Dugong," Zool. Garten, 1896, p. 337.
- Proc. Zool. Soc. 1892, p. 77.