Cambridge Natural History Mammalia/Chapter XVII
Order XIII. PRIMATES.
The highest of mammals, the Primates, may be thus differentiated from other groups:—Completely hairy, generally arboreal mammals, with five digits on fore- and hind-limbs, provided with flat nails (except in the case of certain Lemurs and the Marmosets), the phalanges that bear these being flattened at the extremity and expanded rather than diminished in size. The fore-feet are grasping hands as a rule, and the hind-feet walking as well as (generally) grasping organs, and the mode of progression is plantigrade. The teats, except in Chiromys, are thoracic, and even axillary in position. The skull is characterised by the fact that the orbital and the temporal vacuities are, at least partly, separated by bone. The clavicles are always present. The carpus has separate lunar and scaphoid bones, and the centrale is often present. There is rarely an entepicondylar foramen in the humerus, except in some archaic Lemurs. The femur has no third trochanter. The stomach is usually simple, being sacculated only in Semnopithecinae. The caecum is always present, and often large.
This great group could be easily divided into two separate orders, the Apes and the Lemurs, if it were not for certain fossil types. As will be seen from the description of Nesopithecus and of Tarsius, the actual hard and fast lines between all Apes and all Lemurs are very few. On the other hand, it is a little difficult to draw a hard and fast line between the Primates as a whole—or at least between the Lemurine section—and the Creodonta, a group to which so many others appear to converge. It is disputed, for example, whether the Chriacidae among extinct Lemurs are rightly placed, or whether they should be referred to the Creodonta. The number of primitive characters seen among the Primates, even in Man himself, is remarkable. Of these the more important are the five digits of both limbs and the plantigrade walk, the presence of clavicles and of a centrale, and the absence of a third trochanter. All these features distinguish the early Eutheria.
Sub-Order 1. LEMUROIDEA.
The animals known as Lemurs, from their nocturnal and ghostly habits, are on a lower level of organisation than the other division of the Primates. Even the external form enables the members of the present sub-order to be readily distinguished from the higher Anthropoidea. The head is more like that of a Fox, with a sharp muzzle; it lacks the human expression of the face of even the lower among the Apes. The long tail is never prehensile, and there is never any trace of cheek pouches or of integumental callosities, which are frequently so characteristic of the Apes. The Lemurs agree with the remainder of the Primates in having pectoral mammae (sometimes abdominal ones are present in addition, and in Hapalemur—in the male at least—there is a mamma upon each shoulder), in having opposable thumbs and toes, and in the flattened digits. The tail varies from complete absence (in the Loris) to a great length and bushiness in the Aye-aye. The pectoral limbs are always shorter than the hind-limbs; the reverse is occasionally the case in the Anthropoidea. A curious contrast between the two divisions of the Primates concerns the digits of the hands and feet. In the Anthropoidea it is the hallux or pollex which is subject to great variation. In the Lemurs, on the contrary, the thumb and great toe are always well developed, but the second or the third digit constantly shows some abnormality; thus the singular elongation of the third digit of the hand in Chiromys and the absence of the index in the Potto. In all Lemurs the second toe is furnished with a sharp nail, unlike the flattened nails of the other fingers and toes, and in Tarsius the third also is thus provided. As to osteology, the shape of the head, already referred to, indicates some of the differences in the skull which mark off the Lemurs from the Anthropoidea. The brain case is small relatively to the face; the orbital and temporal fossae are in communication, though the frontal and jugal bones are united behind the orbit. The two halves of the lower jaw are not invariably ossified to form one piece, as is the case with most Apes. The lachrymal foramen lies upon the face in front of the orbit. The teeth are characteristic, not so much in their number (the dental formula is usually I 2, C 1, Pm 3, M 3 = 36) as in the disposition of the incisors. The incisors of the lower jaw and the canines project forwards in a way only found in a few American Monkeys; as in the Apes there are four incisors in each jaw, but, with the exception of the highly aberrant Chiromys, there is a space in the upper jaw between the incisors of the two sides. The canines of the lower jaw, moreover, are often incisiform. There is a well-developed sublingua beneath the tongue (see p. 61). The stomach is perfectly simple; and the caecum, always present and varying in length, never has a vermiform appendix. The gall-bladder is always present. The brain differs from that of the Anthropoidea in that the cerebellum is, as in the lower Mammalia, exposed. The convolutions upon the cerebral hemispheres are not greatly developed, a circumstance, however, which (see p. 77) may have more relation to the size of the animals than to their mental development. Though the brain in its general outlines is not like that of the other Primates, there are certain resemblances; the most striking of these is perhaps the presence, though in rather a rudimentary condition, of the "Simian fissure."
The Lemurine brain has been chiefly studied by Flower, by Milne-Edwards, and by myself. There are also a number of scattered papers dealing with particular types, such as the memoirs of Owen and Oudemans, upon the brain (and the general anatomy) of Chiromys. Without going into great detail it may be stated generally that the anatomy of the brain of this group confirms the classification which is adopted in this work.
A curious feature in the anatomy of the Lemurs, which they share with animals so remote from them in the system as the Edentata, is the breaking up of some of the arteries of the limbs to form retia mirabilia; nothing of the kind is known among the other Primates.
Perhaps the most remarkable difference between the Lemurs and the Anthropoidea, which are really in many respects more closely allied than might be inferred from the above summary of differences, is in the structure of the placenta. The Lemurs agree with the Ungulates in having a non-deciduate placenta.
A curious feature confined to the sub-family Lemurinae was first discovered by myself in Hapalemur griseus. On the forearm (see Fig. 258) is an area of hardened skin, which is raised into spine-like processes. Fully developed, this organ is characteristic of the male, the area being marked off in the female, but without the spiny outgrowths. On removing the skin a gland about the size and shape of an almond is brought into view. In other Lemurs there is no modified skin, but a small tuft of particularly long hairs, which are also present in Hapalemur, and a small gland beneath the skin. The gland of Hapalemur may be comparable with a tract of hardened skin in Lemur catta, which projects to a large extent and has been spoken of as a "climbing organ."
An almost exactly similar tuft of spine-like outgrowths exists upon the lower end of the ankle of Galago garnetti. The spines are black and bent, just as they are in Hapalemur. There appears also to be a gland. This structure is not universal in the genus Galago any more than is the patch of spines in the genus Hapalemur.
In addition to this gland and to the patch of spines which cover it, the same Lemur as well as Chirogaleus and certain species of Lemur possess to the inner side of it a bundle of long and stiff bristles associated with unusually large sebaceous glands; these structures are, of course, not homologous with the gland of the arm of Hapalemur, as they coexist in the same species. They are, moreover, not peculiar to the Lemurs, but exist in the Squirrel, in the Domestic Cat, in the Leopard, in Bassaricyon, the Otter, various Marsupials, and doubtless in many mammals which require a tactile organ, for these hairs are associated with a large branch of the radial nerve.
Fig. 258.—A, left arm of Hapalemur griseus ♂. 'a', Teat; b, spines on arm gland; c, tactile bristle. B, left foot of Nycticebus tardigradus. 1 to 5, Pads upon sole of foot. (After Sutton, and Mivart and Murie.)
The Lemurs have at the present time a most remarkable distribution. There are altogether about fifty species, referable to seventeen genera. Thirty-six species are confined to Madagascar and to some small neighbouring islands. The rest occur in the Ethiopian and in the Oriental region. The rest of the world is at present totally without Lemurs, though, as will be seen in the sequel, the order was more widely spread over the globe in past times.
Fam. 1. Lemuridae.—This family can be usefully subdivided into four sub-families.
Sub-Fam. 1. Indrisinae.—This sub-family is limited to Madagascar, and has been exhaustively treated of by M. Grandidier and Professor Milne-Edwards in the Histoire de Madagascar. These Lemurs contrast with others by the large size of the hind- as compared with the fore-limbs. The ears are short. The tail varies in length. The thumb is but slightly opposable, and the toes are webbed. Correlated with the first two of these characters, these Lemurs when upon the ground progress by means of the hind-limbs, holding their arms above their heads. The number of teeth is reduced, the total being thirty. The formula is I 2/2 C 1/0 Pm 2/2 M 3/3. The colon or large intestine, as figured by Milne-Edwards, has a remarkable watch-spring-like coil, highly suggestive of the Ruminants and of certain Rodents. This, however, is only in Propithecus and Avahis. The caecum in this sub-family is specially large. The brain is characterised by the comparatively slight development of the angular fissure in Propithecus and Avahis; it is in them anterior in position. In Indris it is more -shaped and larger as in Lemur. The parieto-occipital fissure is fairly well developed, so too is the antero-temporal.
The genus Indris has more pronounced external ears than have the two other genera of the sub-family. The tail is rudimentary. The incisors of the upper jaw are sub-equal and set close together, those of the lower jaw have marked longitudinal ridges upon the outer surface, which suggests Galeopithecus (see p. 520). The molars are quadricuspidate. There is but a single species, I. brevicaudata, which is of a black colour, diversified with white upon the rump and the limbs. The term "Indri" means, as does "Aye-aye," "look." One of the native names for the animal, "Amboanala," signifies "dog of the forest," and is derived not only from the woeful howls of the creature, but from the fact that in certain parts of the island it is used as a dog to chase birds.
These howls are largely effected by means of a laryngeal pouch, which is described as different from that of Apes; the mechanism must also differ from that of Megaladapis, inasmuch as the lower jaw is not deep as in that extinct Lemur. The Indri is the largest of Lemurs, measuring about two feet in length. It is arboreal and social, travelling in large companies. As is the case with the Propithecus, the natives of Madagascar hold the Indri in awe and veneration. It is curious that the name Lemur or ghost is peculiarly applicable to the Indri or Babakote in another sense from that which led to its adoption by Linnaeus. The natives, in fact, believe that men after death become Indris. Naturally, therefore, these Lemurs have reaped the advantage of this superstition in almost perfect immunity from destruction. Their "long-drawn-out, melancholy cries" are probably at the root of much of the ghostly terrors which they inspire.
The genus Avahis has but a single species, A. laniger, which is the smallest of this sub-family. It is a foot long without the tail. The Avahi has a long tail (15 inches in length) like Propithecus. The outer incisors are larger than the inner, thus differentiating the genus from Propithecus. The molars of the upper jaw are quadricuspidate, of the lower jaw five cusped. This genus has only eleven pairs of ribs instead of the twelve of Indris and Propithecus. The Avahis, unlike the Sifakas and Indrinas, lead a solitary life, or go about in pairs. They are, moreover, completely nocturnal.
The genus Propithecus is characterised by the fur being rather silky than woolly, which latter is the kind of fur found in the two other genera of the sub-family. They are also rather larger animals, the body reaching a length of nearly 2 feet. The tail is long as in Avahis; the inner incisors are larger than the outer. The "Sifakas," as these Lemurs are termed, have a reputation for gentleness of character, but, as is the case with other animals, the males fight for the possession of the females at the breeding season. They are mainly vegetarian in habit, and travel in large companies. There are at least three species, and several varieties are allowed. The colours of these Lemurs are bright, and distributed so as to form contrasting bands; thus P. coquereli, a variety of P. verreauxi, has a black face and a body mainly white, with splashes of a rich maroon upon the limbs and upon the chest.
These Lemurs are diurnal, and are especially active in the early morning and evening, sleeping, or at any rate remaining quiet, during the heat of the day. Their fitness for an arboreal life is shown by the existence of a parachute-like fold of skin between the arms and the body, which suggests a commencement of the more complete parachute of Flying Foxes, etc. These Lemurs are said to be reverenced and therefore shielded from injury by the natives of Madagascar.
Sub-Fam. 2. Lemurinae.—The "True Lemurs" are all inhabitants of Madagascar and of the Comoro Islands. They have not such long hind-limbs as have the members of the last sub-family, nor are the toes webbed. The tooth formula differs from that of the Indrisinae in that there is one more premolar on each side of the upper jaw, and often one more incisor in the lower jaw, making thus a total of thirty-six teeth. Sometimes, however, the incisors of the upper jaw are totally wanting.
The Hattock, genus Mixocebus, is a scarce creature, only known from a single species, M. caniceps. As it is rare, nothing is known of its habits. It has one pair of upper incisors. The creature is one foot and half an inch long, exclusive of the tail, which is an inch longer than the body.
Genus Lepilemur.—The Lemurs belonging to this genus, entirely confined to Madagascar, as are all the Lemurinae, have received the perfectly unnecessary and pseudo-vernacular name of "Sportive Lemurs"; an equally inappropriate and not at all ingenious name of "Gentle Lemurs" being bestowed upon the allied genus Hapalemur. In Lepilemur there are seven species, which are to be distinguished from Mixocebus in having the tail shorter than the body. There are no incisors in the upper jaw. The last molar is tricuspidate in the upper jaw; that of the lower jaw has five cusps. They are nocturnal creatures, and but little is known of their habits. Previously to Dr. Forsyth Major's visit to Madagascar only two species of the genus were known; he has added five others. The length of the body is 14 inches, and that of the tail 10 inches, in L. mustelinus, which is the largest species.
The genus Hapalemur has a shorter muzzle than Lemur, and shorter ears. There are two pairs of mammae instead of only one; these are upon the breast and abdomen. In the male there is a pair upon the shoulder. The incisors are small, sub-equal, and placed one behind the other; the last one is at the inside of the canines. The molars of the upper jaw and the last premolar have only three well-marked cusps; in the lower jaw they have four. The caecum is blunter and is not so long as in Lemur; it differs from that of other Lemurinae in having only two supporting mesenteries, which are both furnished with blood-vessels. As in Lepilemur and the Indrisinae the carpus has no os centrale.
The genus, which is confined to the island of Madagascar, has two species, of which one, H. simus, is the larger and has a broader muzzle, and does not possess the peculiar arm gland (Fig. 258) already described in H. griseus. The former species is stated by Mr. Shaw to be chiefly a grass-eater, and to dislike berries and fruits, which are usually so popular with Lemurs. It is, however, believed by some that there is but one species of Hapalemur. H. griseus is 15 inches long, and has a tail of the same length. Its native name is "Bokombouli." It is nocturnal, and is especially addicted to bamboos, upon the shoots of which it feeds and among which it lives. It is often exhibited in the Zoological Society's Gardens; but the specimens seem to be always males. This Lemur is of a dark iron-grey colour with a tinge of yellow, more marked in individuals which have received the separate specific name of H. olivaceus.
The genus Lemur is distinguished by the long tail, half as long as the body at the least, by the elongated face, and by the Fox-like muzzle; the teeth are present to the full number of the family, viz. thirty-six; the incisors are small and equal in size, and are separated from each other and from the canines by spaces. The molars of the upper jaw have five cusps, but there are only four in the lower jaw.
This genus is entirely confined to Madagascar and the Comoro Islands, and consists of several species, the exact number of which is doubtful. Wallace in his Geographical Distribution allows fifteen; Dr. Forbes only eight, with a plentiful allowance of varieties. One of the best-known species is Lemur catta, the Ring-tailed Lemur, or the "Madagascar Cat" of sailors. Lemur macaco shows a remarkable sexual dimorphism, the male being black, and the female—formerly described as a distinct species, L. leucomystax—being reddish brown with white whiskers and ear tufts. This led to a confusion with a totally distinct species, L. rufipes, of which the male (regarded as distinct and called L. nigerrimus) is entirely black. This latter identification is, however, considered by Dr. Forsyth Major to be not quite certain at present.
The young Lemur is at least sometimes carried by the mother across her belly; its tail passes round her back and then round its own neck.
Fig. 259.—Ruffed Lemur. Lemur varius. × 1⁄9.
The Lemurs of this genus agree with those of some other genera in the loudness of their voice, which is constantly exercised. Some move about by day and others by night. They are insectivorous and carnivorous as well as vegetarian; and Mr. Lydekker suggests that their abundance and hardiness is to be traced to this fondness for a mixed diet. Lemur catta seems to be the only member of the genus that is not arboreal. It lives among rocks where but few trees, and those much stunted, occur. Many species of Lemur are always to be seen in the Zoological Society's Gardens. Fourteen "species" have at one time or another been exhibited.
Sub-Fam. 3. Galagininae.—This sub-family is found on the continent of Africa as well as in Madagascar; but the genera are different in the two districts. In Madagascar we have Opolemur, Microcebus, and Chirogale; on the continent, Galago. The members of this sub-family have markedly large ears, which are but little furry; the tail is long. A very marked skeletal character distinguishes this sub-family from other Lemuridae, and allies them to Tarsius, that is the lengthening of the calcaneum and naviculare in the ankle. The dental formula is as in Lemur. The supporting bands of the caecum are in this sub-family as in the genus Lemur. There are but two folds, of which one is median and non-vascular; the lateral fold bears a blood-vessel, and is joined by the median frenum. The brain is but little known. The only figure of the brain of Galago is one by myself. There are four mammae, two on the breast and two upon the abdomen.
The genus Galago comprises at any rate six distinct species. They are all African, and range right across the continent from Abyssinia as far south as Natal, and to Senegambia in the west. The incisors of the upper jaw are small and equal; there is a gap between the canine and the first premolar. The molars and the last premolar have four cusps; the last molar of the lower jaw has an additional fifth cusp as in Macacus, etc. The Galagos are chiefly nocturnal, and are more or less omnivorous. Owing to their long hind-legs these animals when they leave the trees advance upon the ground by hops like a Kangaroo. Galago senegalensis makes a nest in the fork of two branches, where it sleeps during the day. The Great Galago (G. crassicaudatus) is named by the Portuguese "Rat of the Cocoa-nut Palm." Sir John Kirk, after whom a variety of this species is called, relates that it is incapable of resisting the fascinations of palm wine, upon which it will readily intoxicate itself, and as a consequence brave probable captivity. I have referred above (p. 536) to the patch of spines upon the tarsus of G. garnetti.
The genus Chirogale is entirely confined to Madagascar. It is to be distinguished from Galago by the fact that the inner incisors are larger than the outer. There are five species of the genus known: four previously to Dr. Forsyth Major's recent visit to Madagascar, and a fifth brought back by him. In connexion with this genus the naturalist just mentioned has observed that all the Lemurs of Madagascar, including the aberrant Chiromys, differ from the African forms by the fact that the tympanic ring "is completely enclosed by the bulla ossea, but without osseous connexion with the same." This character he thinks so important as to justify the inclusion of all the Mascarene forms in one group as opposed to another group consisting of the continental Lemurs. In this event Chirogale will have to be separated from its close association with Galago. For the present, however, it is left in the more generally accepted position.
Fig. 260.—Smith's Dwarf Lemur. Microcebus smithii. × ¾.
Fig. 261.—Mouse Lemur. Chirogale coquereli. × ½.
Microcebus contains the most minute among the Lemurs. M. smithii has a body only 5 inches long, the tail being another 6 inches. It occurs in Madagascar, and includes five species.
Opolemur, the Fat-tailed Lemur, was so called on account of a deposit of fat formed chiefly at the root of the tail, and intended to tide over the time of the creature's hibernation. But, as a matter of fact, this peculiarity also exists in Chirogale. Of Opolemur but two species are known, and of one of these, named after Mr. Thomas of the British Museum, only three examples are in existence in museums, that is to say in one museum—our own at South Kensington. Many of these dwarf Lemurs are exceedingly rare. In this genus and in the last two the palate has a pair of posterior fenestrae, of which there are also traces in other Lemurs, but which are particularly large in Microcebus. This is, of course, a well-known character of the Marsupials, and also, which is more important in the present connexion, of certain Insectivores.
Sub-Fam. 4. Lorisinae.—This sub-family is the only one with a wide distribution, and it contains, with the exception of Tarsius, the only Asiatic members of the group. Correlated with its wide distribution there is more divergence in anatomical characters than is the case with the other sub-families of the Lemuridae. In external features all the three genera of this sub-family agree in their small size, their short or entirely deficient tail, large staring eyes, and the rudimentary character, or absence, of the index finger, which is never provided with a nail; in all of them the thumb diverges widely from the other fingers, and the great toe is so divergent as to be directed backwards. In the brain there is one character common to all three genera, and that is the small length of the angular fissure. The caecum, which is long, is supported by three folds, of which the median is anangious, and is sometimes attached to the longer of the two lateral folds, which are vascular. The members of this sub-family have more dorsal vertebrae than are found in other Lemurs; the range is from fourteen in Loris, to sixteen in Nycticebus.
The genus Nycticebus contains only a single species, N. tardigradus, though four other names have been given to supposed varieties. Moreover, the genus itself has been named Stenops, as also the next genus Loris. The body of this animal is stouter than that of the next to be described. Professor Mivart has pointed out that, though Asiatic like the Loris, it presents more resemblances to the African Potto. The index finger is small; the inner of the two incisors is smaller than the outer, but both of one side are close together. They may be reduced to one on each side of the upper jaw.
Fig. 262.—Slow Loris. Nycticebus tardigradus. × ⅓.
The animal has a wide distribution in the East, occurring in Assam and Burmah, the Malay Peninsula, Siam, and Cochin-China, Sumatra, Java, Borneo, and the Philippines. Its vernacular names signify "Bashful Cat" and "Bashful Monkey" in allusion to its nocturnal and shy habits. It lives among trees, which it does not voluntarily leave. Its movements are deliberate, as its popular name, Slow Loris, implies; but it makes up for this by a vigorous tenacity of grasp. The animals "make a curious chattering when angry, and when pleased at night they utter a short though tuneful whistle of one unvaried note, which is thought by Chinese sailors to presage wind." Much superstition has collected round this harmless though rather weird-looking creature. Its influence over human beings is as active when it is dead as when it is alive. "Thus," writes Mr. Stanley Flower, "a Malay may commit a crime he did not premeditate, and then find that an enemy had buried a particular part of a loris under his threshold, which had, unknown to him, compelled him to act to his own disadvantage." The life of the Loris, adds Mr. Flower, "is not a happy one, for it is continually seeing ghosts; and that is why it hides its face in its hands!"
The genus Perodicticus contains two quite recognisable species, known respectively as the Angwantibo and Bosman's Potto. The former has been regarded as referable to a distinct genus, Arctocebus. A curious internal character of the Potto which is visible, or at least can be felt, externally, is the long neural processes of the cervical vertebrae, which project beyond the level of the skin. The index finger is rudimentary and so is the tail, being only just visible (about an inch in length) in the Potto. The colour of both genera is a reddish grey, redder in the Potto. The incisors are equal and minute. Both species are confined in their range to West Africa, and are arboreal like the other members of the sub-family. The Potto seems to share the leisurely mode of progression of its Asiatic relatives, if Bosman, its original describer, is to be trusted. He says: "By the negroes called Potto, but known to us by the name of Sluggard, doubtless from its lazy, sluggish nature; a whole day being little enough for it to advance ten steps forward." The same writer did not at all appreciate his addition to zoological knowledge, for he remarked that the Potto "hath nothing very particular but his odious ugliness." The Angwantibo is rare and but little known. Our knowledge of its anatomy is derived from a paper by Huxley. It is an animal measuring about 10½ inches in total length to the end of the tail, which is only a quarter of an inch long. The hands and feet are smaller than those of Perodicticus. The index finger is rudimentary and has but two phalanges, and it has no trace of a nail. In this it agrees with the Potto, but "the spinous processes of the cervical vertebrae do not project in the manner described by van der Hoeven in the Potto, though they can be readily felt through the skin." The dental formula of this genus as of the last is I 2/2 C 1/1 Pm 3/3 M 3/3. The last lower molar has a fifth cusp, which is wanting in the Potto. The last upper molar is tricuspid. It is bicuspid in the Potto. It seems impossible to avoid agreeing with Professor Huxley that the Angwantibo is entitled to generic separation.
The genus Loris also contains but a single species, L. gracilis, and is, as its name denotes, an animal of more slender build than the Slow Loris. Its eyes are very large, and the limbs excessively slender. The index finger is much as in Nycticebus. The colour, too, is not widely different, being of a yellowish grey, but it lacks the dorsal stripe which distinguishes its relative. The incisor teeth are equal and very small. The last upper molar has four cusps instead of the three of Nycticebus. This Lemur is confined to Southern India and Ceylon, and has much the same habits as the last. But it is rather more active, and can capture small birds when sleeping upon the trees; its diet, however, is mixed, and is vegetarian as well as animal.
A mysterious Lemur, which we conveniently place as a kind of appendix to the present family on account of its locality, has been shortly described by Nachtrieb from the Philippines. The tail is rudimentary; there are two upper incisors, but as many as six lower. It is doubtful what the beast really is.
Fig. 263.—Aye-aye. Chiromys madagascariensis. × 1⁄10.
Fam. 2. Chiromyidae.—This family contains but a single genus and species, the Aye-aye, Chiromys madagascariensis, whose characters therefore are for the present those of the family as well as of the genus and species. The external features of this extraordinary animal will be gathered from an inspection of Fig. 263, from which it will be seen that the earlier name of Sciurus given to the creature was not by any means a misnomer. The Squirrel-like appearance is due, of course, chiefly to the strong and long incisor teeth. As to the external characters, which are of systematic importance, attention may be called to the long and bushy tail, to the greater length of the hind-limbs, to the abdominal teats (one pair) in the female, and above all to the singular third digit of the hand, which is thin and elongated. The thumb is, as in other Lemurs, opposable, and has a flat nail; the remaining digits have claws, as have also the toes with the exception of the great toe, which has a flat nail like the thumb.
The anatomy of this animal has occupied the attention of a considerable number of observers, dating from Sir R. Owen, who was the first to give a connected account of its entire organisation. The most recent paper of importance is by Dr. Oudemans. The teeth are very unlike those of other Lemurs. The most remarkable divergence is in the incisors, which are present to the number of but a single pair in each jaw, and are shaped like those of the Rodentia, and in the same way as in that group grow from persistent pulps. There are likewise, as in the Rodents, no canines. There are two premolars in the upper jaw (none in the lower) and altogether twelve molars, so that there is a total of eighteen teeth. The intestine has a moderately long caecum. The brain has been most fully described by Oudemans, who had fresh material to work with, the brain described by Owen having been extracted from a spirit-preserved carcase. The angular fissure is well developed, as in Lemur and the Indri; but it does not join the infero-frontal. The antero-temporal fissure is also well developed.
"The name of Aye-aye," wrote Sonnerat, the discoverer of the animal, "which I have retained for it, is a cry of surprise of the inhabitants of Madagascar." It is, however, usually said that the animal itself makes a sound which may be written in the same way (or with an initial H). It is an arboreal and nocturnal animal, which accounts for its excessive rarity at one time. In one of his many eloquent essays upon natural history the late Mr. P. H. Gosse adduced the Aye-aye as an example of a creature on the verge of extinction. It is, however, now more frequently met with, though the superstition of the natives renders its capture a matter of some difficulty. There is a specimen at the moment of writing in the Zoological Society's Gardens. There has been some discussion as to the use of the slender middle finger: it is stated that it can thrust it into the borings of the larva of a certain beetle of which the Lemur is particularly fond, and can extract the insect, or at any rate discover its position, when it may be extracted by the powerful chisel-shaped teeth. The partiality of the Aye-aye for animal food of any kind including insects has been both reaffirmed and denied; and Mr. Bartlett has seen the creature use its slender finger for combing out its hair, and for other purposes of the "toilet." Dr. Oudemans has figured in his paper an apple which has been largely eaten by the Chiromys; the fleshy pulp has been entirely excavated, leaving only the core and the skin, which are untouched. The Rev. Mr. Baron is one of the latest writers upon the ways of life of Chiromys. He states that it inhabits the most dense parts of the forests. It has the habit of prowling about in pairs, and the female produces but a single young one at a birth. A nest, which is about 2 feet across, is made of twigs in lofty branches. This is occupied during the day, and entered by a hole in the side. With regard to the superstitious veneration in which the animal is held, it is said that if a person sleeps in the forest the Aye-aye will bring him a pillow. "If a pillow for the head, the person will become rich; if for the feet, he will shortly succumb to the creature's fatal power, or at least will become bewitched." But a counter-charm may be obtained. It is said that the reverence for this beast leads the natives to bury carefully a specimen found dead.
Fam. 3. Tarsiidae.—This family also consists of but a single genus, Tarsius, to which it is the general opinion that but a single species belongs; there are, however, at least four different specific names on record. The general aspect of the animal is not unlike that of a Galago, with which it also agrees in the elongation of the ankle; but the elongation is more pronounced in the present genus. The ears are large, and the eyes are extraordinarily developed. The fingers and toes terminate in large expanded discs, and are furnished with flattened nails except on the second and third toes, which have claws. The tail is longer than the body and is tufted at the end. The skull is more like that of the Anthropoidea than is the skull of any other Lemur. The resemblance is by reason of the almost complete separation of the orbit and the temporal fossa by bone; there is, however, a gap left to mark the Lemurine characters of the animal. The placenta, too, has been compared to that of the Apes. The dental formula is that of the genus Lemur, save for the absence of an incisor on each side of the lower jaw; the number of teeth is therefore thirty-four. The incisors of the lower jaw are upright, and not procumbent as in other Lemurs. The caecum is of moderate length. The brain is almost smooth, but there is a Sylvian fissure and an antero-temporal, which latter does not reach the lower margin of the brain, but divides the middle part of the temporal lobe. The name Tarsier, as may be inferred, was originally given to this creature by Buffon on account of the abnormal ankle, and it was compared by him with the Jerboa, like which animal the Tarsier leaps when it descends to the ground. The genus is Malayan, but its range extends to the Philippines and to Celebes and Borneo. The Tarsiers are nocturnal and particularly arboreal; they live in pairs, in holes in tree stems, and are mainly insectivorous in their food. One, rarely two young are produced at a birth. Contrary to what is found in many Lemurs, the Tarsier is a silent creature, and at most emits a "sharp, shrill call." Dr. Charles Hose, who has studied this creature, has noticed that the mother often carries her young one about in her mouth like a Cat. Like so many Lemurs this animal is held in superstitious dread, which no doubt is the result of its most weird appearance.
Fig. 264.—Right pes of Tarsius spectrum. (Nat. size.) a, Astragalus; c, calcaneum; c1, internal cuneiform; c2, middle cuneiform; c3, external cuneiform; cb, cuboid; n, navicular; I-V, the digits. (From Flower's Osteology.)
Fossil Lemurs.—The Lemuroids are a very ancient race; they extend back to the very earliest strata of the Eocene, the Torrejon and Puerco beds, which, as already said, are thought to be more referable to the Cretaceous than to the Tertiary epoch. One of these early forms is referred to the genus Mixodectes, a genus which has been placed, though with a query, in the order Rodentia. It appears, however, to be a Lemuroid, and is of American range. The incisor teeth have been held to argue that it lies on the direct track of Chiromys; but other features, more especially the form of the astragalus, have been used to argue the justice of the inclusion of this type within the order Rodentia. Allied, as it is supposed, to this form is Indrodon, also of the lowest Eocene deposits of the United States. Indrodon malaris is known from fragments of nearly all parts of the skeleton. They indicate the existence of a creature of about one-half the size of Lemur varius. It had slender limbs and a long and powerful tail. The humerus, as in so many archaic beasts, has an entepicondylar foramen. The femur has three trochanters, and the fibula articulates with the astragalus. It is not always easy to distinguish these primitive mammals from each other, so that the minutest of characters have to be called in to our assistance. One of the contemporaneous groups with which these early Lemurs might be confused is that of the Condylarthra; it is important, therefore, to note that in Indrodon the calcaneo-cuboidal articulation is nearly flat, and not bent as it is in the former group. The teeth are of the tritubercular pattern. The incisors are not known, but the molars and premolars are each three. To the same family, which has been termed Anaptomorphidae, is referred the genus Anaptomorphus, which has been specially compared to Tarsius. This small animal has a Lemurine face with huge orbits. It has a premolar less than Indrodon. It has been ascertained that A. homunculus had an external lachrymal foramen.
Another family, that of the Chriacidae, appear to hover on the border line of Lemurs and Creodonts, having been referred to both by various palaeontologists. Professor Scott suggests their Lemurine or at least Primate relationships, while Cope urged their Creodont affinities. A difficulty raised by Scott was, that in Chriacus the premolars of the lower jaw were spaced. But it appears that this is not fatal to their inclusion in the Primates, since Tomitherium, an "undoubted Primate," shows the same feature. If Chriacus is a Lemur it is an earlier type than those which have been considered; for it has the typical Eutherian dentition of four premolars and three molars. These teeth, especially the superior molars, are particularly compared to the corresponding teeth of Lemur and Galago. Of this and the allied genus, Protochriacus, several species are known.
Adapis, a representative of another family, is one of the best known of ancient Lemuroids. It has the typical mammalian dentition of forty-four teeth in a close series without diastemata. The orbits are completely separated from the temporal cavity, the eyes looking forwards. The canines are large and caniniform. The skull is deeply ridged behind with the usual sagittal crest. This genus is European, and corresponds to the already mentioned American Eocene Tomitherium, perhaps belonging to the same family.
Nesopithecus is an extinct genus from Madagascar, lately described by Dr. Forsyth Major. There are two species, N. roberti and N. australis. The dental formula is I 2, C 1, Pm 3, M 3, for the upper jaw, the lower jaw having but a single pair of incisors. The lachrymal foramen is just inside, or on the edge, of the orbit, so that one distinctive Lemurine character is lost. The genus is also Ape-like in the form of the canines and incisors, these having been especially compared by Dr. Forsyth Major with those of the Cercopithecidae. The molars, too, agree with those of the same family. There is, however, one important feature in which Nesopithecus resembles not only the Lemurs as opposed to the Apes, but the Malagasy Lemurs. As already mentioned (p. 544), Dr. Major has shown that in the Malagasy Lemurs, even including the aberrant Chiromys, and in the Tertiary and European Adapis, the bulla tympani is not produced by an ossified extension of the annulus tympanicus, but from the adjacent periotic bone, the annulus remaining separate and lying within the fully-formed bulla. This feature shows conclusively that Adapis is a Lemur, and that Nesopithecus, originally supposed to be a Monkey, cannot be removed from the Lemuroidea, many though its likenesses to the higher Primates undoubtedly are. However, this feature, combined with the fact that the orbital and temporal cavities are in communication, shows the Lemuroid position of Nesopithecus, though it is quite conceivable that it is on the way to become an Ape.
A family, Megaladapididae, has been quite lately founded by Dr. Forsyth Major to include the remains of a gigantic extinct Lemur from Madagascar, which when alive, so far as we can judge from the skull, must have been three or four times the size of the Common Cat. The name Megaladapis madagascariensis was given to the fossil on account of certain resemblances to the also extinct Adapis. It differs from other Lemurs in a number of characters which jointly warrant its inclusion in a distinct family. The small size of the orbits suggest a diurnal life; the deep mandibles, which, unlike what is found in other Lemurs, are completely blended at the suture, point to the existence of a howling apparatus, as in Mycetes. The low brain-case is a character which is found in so many extinct Mammalia belonging to many different orders that it weighs neither one way nor the other in considering the systematic position of the animal. The shape of the molars, which are three in each half of each jaw as in other Lemurs, is, according to the discoverer, like that of the genus Lepilemur. The incisors and the canines are not known. Of a still larger form, M. insignis, the molar teeth are known.
Sub-Order 2. ANTHROPOIDEA.
The Apes differ from the Lemurs in that the teats are always restricted to the thoracic region; the orbit, though surrounded by bone as in the Lemurs (and in Tupaia, a very Lemur-like Insectivore), does not open freely behind into the temporal fossa as in Lemurs (except Tarsius). The lachrymal opening is inside the orbit instead of outside; the cerebral hemispheres are more highly developed, and conceal, or nearly conceal, the cerebellum; the upper incisors are in close contact; a few other points are mentioned under the description of the characters of the Lemurs. There are altogether about 212 species of Monkeys and Apes. They are tropical and subtropical in range, and, with but few exceptions, are impatient of cold.
The Monkeys are primarily divisible into two great divisions, which have been termed, on account of the characters of the nose, the Catarrhines and Platyrrhines. In the former the nostrils look downward and are close together; in the latter they are separated by a broad cartilaginous septum, and the apertures are directed outwards. But numerous other points of difference separate these two groups of the Monkey tribe. The Catarrhines often have those remarkable ischial callosities, patches of hard skin brightly coloured; the tail may be totally wanting as a distinct organ, as is the case, for instance, with the Anthropoid Apes; there are often cheek pouches, so that, as Mr. Lydekker has remarked, if a Monkey be observed to stow nuts away in its cheeks for future reference, we may be certain that its home is in the Old World, for the Catarrhines are exclusively denizens of the Old World, while the Platyrrhines are as exclusively New World in range. Again, those of the Catarrhines which do possess a long tail, such as the members of the genus Cercocebus, never show the least sign of prehensility in that tail. The teeth of the Catarrhines are invariably thirty-two in number, the formula being I 2/2 C 1/1 Pm 2/2 M 3/3 = 32.
In the Old-World Apes there is a bony external auditory meatus, which is wanting (as a bony structure) in the Platyrrhines. The late Mr. W. A. Forbes pointed out that in most of the New-World forms the parietals and the malars come into contact; in the Monkeys of the Old World they are hindered from coming into contact by the frontals and the alisphenoids. The Platyrrhines may have the same number of teeth; this is the case with the Marmosets, but in them there are three premolars and two molars; in the remaining New-World Monkeys there are thirty-six teeth, but of these three are premolars and three molars.
Not only are these two groups of the Primates absolutely distinct at the present day, but they have been, so far as we know, for a very long time, since no fossil remains of Monkeys at all intermediate have been so far discovered. This has led to the suggestion that the Monkeys are what is termed diphyletic, i.e. that they have originated from two separate stocks of ancestors. It is hard, however, to understand on this view the very great similarities which underlie the divergences that have just been mentioned. But, on the other hand, it is equally hard to understand how it is that, having been separated from each other for so long a period, they have not diverged further in structure than they have. The Platyrrhines seem to stand at the base of the series. This is another example of the existence of archaic creatures in South America.
Group I. PLATYRRHINA.
Fam. 1. Hapalidae.—We may begin the account of the Platyrrhine Monkeys with the Hapalidae or Marmosets; for this family is structurally lower than the rest. They have thirty-two teeth, arranged as in the following formula: I 2/2 C 1/1 Pm 3/3 M 2/2 = 32. The molars have three main tubercles, and not four as in the higher forms. The digits are for the most part clawed, not nailed, as in the higher types; the great toe alone bears a flat nail. The tail, too, is ringed, a condition which is characteristic of many of the lower groups of mammals, but not of the higher Apes. The cerebral hemispheres are smooth, but this is a matter rather connected with their small size than with low zoological position. The tails of the Marmosets, unlike those of so many other American Monkeys, are not prehensile though they are long.
The genus Hapale is broadly distinguished from the other genus, Midas, by the fact that the lower incisors slant forwards as in the Lemurs. They are small, soft-furred, long-tailed Monkeys, familiar to every one. There are some seven species, which are entirely restricted in range to Brazil, Bolivia, and Colombia, one species only, H. pygmaea, extending northward into Mexico.
Of Tamarins, genus Midas, there are rather more species—about fourteen. They are South and Central American in distribution. Since both these genera are arboreal in habit, it is extraordinary that they have not the prehensile tails of their American allies. As, however, the late Mr. Bates observed an individual of the species M. nigricollis fall head-foremost from a height of at least 50 feet, alight on its feet, and run off as if nothing in particular had occurred, it is evident that no extra prehensile powers are absolutely necessary. Some of the Tamarins have a long mane; this is well seen in M. rosalia, or rather in M. leoninus, which, if not identical with it, is at least very closely allied to it. The name is obviously derived from the character referred to, and the Monkey, originally described by the traveller von Humboldt, is said to have "the appearance of a diminutive lion." M. bicolor is an example of the species with no mane, but with a patch of white round the mouth, looking like "a ball of snow-white cotton" held in the teeth.
Fam. 2. Cebidae.—The remaining American Monkeys are comprised in the family Cebidae. This is to be distinguished from the last by the fact that there is an additional molar, thus making thirty-six teeth in all. The tail, sometimes very short, is more generally long and highly prehensile, being nude at the extremity, which part is therefore especially prehensile; this state of affairs is often to be seen in animals with prehensile tails. The Cebidae, though for the most part larger than the Marmosets, never approach in size the Old-World Apes.
Typical of the family is the genus Cebus, including the "Capuchin" Monkeys, and consisting of nearly twenty species; the tail, though prehensile, is covered with hair to the tip, a fact which is indicative of a less perfect prehensility than is exhibited in some Monkeys with a naked under surface to the tip of the tail. The thumb is well developed. The genus ranges from Costa Rica to Paraguay. The commonest Monkey which accompanies the street organs of this country is a Cebus. It is a popular delusion that these and other monkeys are purely vegetable-feeding animals. Cebus is in fact particularly fond of caterpillars, as are also the Marmosets.
Allied to Cebus is Lagothrix, the Woolly Monkey, of which L. humboldti is the best-known species, there being indeed but one other. It is a larger and heavier animal than any species of Cebus; and the Hare-like woolliness of the fur suggested its scientific name to its original describer, von Humboldt. It has a perfectly prehensile tail, naked at the tip. The thumb and great toe are well developed. These are purely fruit-eating Monkeys, and are known as "Barrigudos" by the Portuguese of the Amazon country on account of their prominent belly, due apparently to the immense amount of fruit consumed. They are, or were, much eaten by natives.
Brachyteles is a little-known genus, connecting the last with the next genus. The under fur is woolly; the thumb is small or absent. The tail is naked below.
The Spider monkeys, Ateles or Coaitas, have been described as the most typically arboreal of American monkeys. The use of the prehensile tail can frequently be studied in living examples in the Zoological Society's Gardens. With this "fifth hand" the Monkey feels for a place to grasp, and securely twists its tail round, moving it with the greatest ease from point to point. When the tail is being thus used it is carried erect over the head. The fact that this genus possesses no functional thumb is thought to be associated with the extreme perfection of its adaptability to an exclusively arboreal life. The hand without a thumb can act as an equally efficient hook for suspending the body; and what is useless in nature tends to disappear. These Monkeys have a wide range, extending from Mexico in the north to Uruguay in the south. There are ten species. The flesh of many Monkeys is eaten not only by natives but by Europeans; but the Spider Monkeys are said to furnish the most sapid food of all.
Fig. 265.—Spider Monkey. Ateles ater. × 1⁄12.
The Howling Monkeys, genus Mycetes, have also received the appropriate generic names of Alouatta and Stentor. The former of these two names, indeed, is that which should properly be applied to the genus. But Mycetes is perhaps better known. The "howling" is produced by saccular diverticula of the larynx, larger than those of other American Monkeys, such as Ateles, where, however, they are also developed. The hyoid bones, too, are enormously enlarged and cavernous, while the jaw—in order to accommodate and protect these various structures—is unusually large and deep. The Howlers are furnished with a fully prehensile tail. The thumb is present. They are described as being the most hideous in aspect of the American Monkeys, and of the lowest intelligence, with which latter characteristic is associated a less convoluted brain than in Ateles, for example. The noise produced by these Monkeys is audible for miles, and is said not to be due to emulation, i.e. not to be comparable to singing or talking, but to serve to intimidate their enemies. The story told of these and other Monkeys with prehensile tails, that they cross rivers by means of a bridge of intertwined Monkeys, is apparently devoid of truth. There are six species, which are Central and South American in range.
The Squirrel Monkeys, genus Chrysothrix, are small creatures with a long head, the occiput projecting. Their tail, though long, has no naked area at the extremity and is non-prehensile. It is a remarkable fact that the proportions of the cranium as compared with the face are greater, not only than in other Monkeys, but than in Man himself. The thumb is short, but not so short as in the Spider Monkeys. The cerebral hemispheres are very smooth; but, as already remarked, this is a matter of size, and not of low position in the series. It may appear at first sight that this statement contradicts the one made concerning the Howlers. But the latter are large Monkeys, and therefore ought, so to speak, to have a more complex brain; but they have not. Like so many of the American Monkeys, the Squirrel Monkeys are gregarious, and, in spite of their tails, arboreal. They are largely insect-feeders, and also catch small birds and devour eggs. There are four species, of which C. sciurea is the commonest, and is constantly an inmate of the Zoological Society's Gardens. Humboldt asserted of it that when vexed its eyes filled with tears; but Darwin did not succeed in seeing this very human expression of an emotion.
Callithrix is a genus not far removed from the last, and, like it, occurs both in Central and in South America. It is chiefly to be distinguished from Chrysothrix by the non-extension backwards of the head, and by the more furry character of the tail. The lower jaw is rather deep, as in the Howlers; but there is not, or there has not been discovered, a howling apparatus like that of Mycetes. Nevertheless Professor Weldon has found in a female of C. gigot a patch of ossification on the thyroid cartilage of the larynx which may be an indication of something more in the male. There are eleven species.
Nyctipithecus, the Doroucouli Monkeys, is a genus of somewhat Lemurine appearance, caused by their large eyes. But they reminded Bates of an Owl or a Tiger-cat! They have a long, but not prehensile tail. As in the Marmosets, the lower incisors project forwards in a Lemurine fashion. The thumb is very short. A peculiarity of this genus is the twenty-two dorso-lumbar vertebrae. As in Chrysothrix, but not as in Callithrix, the hemispheres of the brain are smooth. There are five species, of which one occurs so far north as Nicaragua; the rest are Brazilian, extending down to the Argentine.
Fig. 266.—Red-faced Ouakari. Brachyurus rubicundus. × 1⁄5.
The Ouakari Monkeys, Brachyurus, are, as the name denotes, short-tailed forms. Two species, B. rubicundus and B. calvus, have bright red faces; B. melanocephalus has a black one. There is a small thumb. The brain is fairly convoluted, and is to be specially compared with that of Cebus and Pithecia. The species B. rubicundus at any rate has an absolutely as well as a relatively greater length of intestines and caecum than any other American Monkey known.
Fig. 267.—White-nosed Saki. Pithecia albinasa. × 1⁄5. (From Nature.)
Not the least remarkable fact about these Ouakari Monkeys is their distribution in South America. We cannot do better than quote the summary given by Messrs. P. L. and W. L. Sclater in their Geography of Mammals, which is as follows: "Each of them, as first shown by Bates and afterwards further explained by Forbes, is limited to a comparatively small tract of forest on the banks of the Amazon and its affluents. The Black-headed Ouakari (B. melanocephalus) ... is met with only in a tract traversed by the Rio Negro; the Bald-headed Ouakari appears to be confined to the triangle formed by the union of the Amazon with another affluent, the Japura; and the Red Ouakari to the forests on the north bank of the Amazon opposite Olivença, and lying between the main stream and the River Iça. Each of them evidently takes the place of the others in its particular district. Of this peculiar kind of distribution few instances are known amongst mammals, but many somewhat similar cases have been observed in birds, reptiles, and insects."
The genus Pithecia, the Sakis, consists of five species with long bushy tails, which are non-prehensile. They are bearded and have a thumb. Like the last genus, Pithecia does not extend into Central America. The incisors project forwards, and the lower jaw is deep, though the howling apparatus of Mycetes is wanting. The thin, closely-set, and projecting incisors are very suggestive of those of the Lemurs. Brachyurus is much like Pithecia in this respect, and both differ markedly from such a genus as Cebus, where the lower incisors are vertical. An anatomical peculiarity of Pithecia is the breadth of the ribs. P. satanas is perhaps the best-known species, but all five have been exhibited at the Zoological Society's Gardens. As its name suggests, P. satanas is entirely black; it shows a curious point of difference from P. cheiropotes in its way of drinking. The latter species, as its name denotes, uses its hand to drink, while P. satanas puts its mouth to the water. P. albinasa is black with a red patch on the nose, within which again is a small white patch.
Group II. CATARRHINA.
The Catarrhine Apes are divisible into three or perhaps only two families, the Cercopithecidae and the Simiidae, to which must be added the Hominidae. The Simiidae are sometimes spoken of as the Anthropoid Apes.
Fam. 1. Cercopithecidae.—Of the Cercopithecidae there are eight genera (perhaps nine) to be recognised, which may be distributed into two sub-families. The first of these two sub-families, that of the Cercopithecinae, has the following characters:—There are cheek pouches in which the animals store food temporarily. The stomach is simple and globular; this corresponds with a mixed diet. The tail is long or short, or practically absent.
Fig. 268.—Tcheli Monkey. Macacus tcheliensis. × 1⁄6. (From Nature.)
The most familiar genus is undoubtedly Macacus. This includes all the common so-called Macaques, the Bonnet Monkey, the Pig-tailed Monkey, etc. In this genus we find that the males are larger than the females, and have stronger canine teeth. Ischial callosities are well developed. The genus is purely Asiatic, reaching as far east as Japan, with the exception of the Barbary Ape, M. inuus, also known as the Gibraltar Ape. There are altogether some seventeen species.
Macacus inuus is doubtfully indigenous to Gibraltar. It is, however, definitely established there at present, and is carefully fostered. It is a large Ape with no external tail, in which particular it is unique among the members of its genus. At one time its extinction on the "Rock" was nearly accomplished, but three individuals being known. In 1893 the Governor of Gibraltar informed Mr. Sclater that he had himself counted as many as thirty in one herd. Its depredations seem to have led to the expression of a wish in some quarters that the numbers should be thinned; but feeling on the opposite side appears to be stronger, so that whatever was the actual mode of its introduction on to the "Rock" it will at any rate remain there unmolested for the present.
M. tcheliensis is a species found in the Yung-ling Mountains in North China. It is, with the possible exception of M. speciosus, the most northerly form of Monkey. It is interesting on account of the fact that like the Tiger of those regions it has put on an extra coating of fur to enable it to combat with the bitter winters. It is doubtful whether it is more than a variety of the Rhesus Monkey (M. rhesus).
M. nemestrinus, "the Pig-tailed Macaque," is trained by the natives of the east to climb cocoa-nut palms and to carefully select and throw down only the ripe fruit. Sir Stamford Raffles apparently was the first to report upon this useful intelligence of the animal, and Dr. Charles Hose of Borneo has confirmed him.
The Japanese Macaque (M. speciosus) is well known from the work of Japanese artists. It is the only species of Monkey found in Japan, and goes very far north.
A rather rare form is M. leoninus. It has a short tail, and occurs in Burmah. M. silenus is distinguished by a ruff of long light-coloured hair surrounding the face. It is sometimes called the Wanderoo; but this is apparently quite inaccurate, since that term is used by the Ceylonese for a Semnopithecus. For those who wish a "pseudo-vernacular" name Dr. Blanford suggests Pennant's name of "Lion-tailed Monkey."
The commonest species of the genus are M. cynomolgus, M. sinicus, and M. rhesus.
The genus Cercocebus, including those Monkeys known as Mangabeys, is confined to West Africa. They have always a long tail, quite as long as the body. The upper eyelids are pure white in colour. The ischial callosities are more pronounced than in the Macaques. In the Mangabeys also the hairs are not ringed with differently coloured bars, as is the case with both Macaques and Cercopithecus, giving to them the greenish hue which characterises so many of the last two genera. There are no laryngeal air sacs as in the Macaques. There are not more than seven species.
The genus Cercopithecus (the Guenons) represents in Africa the Oriental and Palaearctic Macaques; the genus has a long tail. The cheek pouches are larger than in the genus Macacus. The ischial callosities are less extensive than in that genus. A tooth character also distinguishes this genus from Macacus; the last molar of the lower jaw has, as a very general rule, only four cusps instead of the five which are found in Macacus. The supraciliary ridges in the skull are by no means so marked as in the allied genera.
One species, the Talapoin, C. talapoin, has been separated into a distinct genus, Miopithecus, on account of the fact that the lower molars have only three tubercles instead of the usual four. But if this be done, then Cercopithecus moloneyi, which has a lower molar with five tubercles, should also be separated.
Fig. 269.—Diana Monkey. Cercopithecus diana. × 1⁄6.
The genus Cercopithecus is limited to Africa, and its numerous species have often a very limited range. They are frequently rather brightly coloured, with blue and white patches on the face. The Diana Monkey has a pointed white beard. Of the Vervet Monkey (C. lalandii) a curious fact was noticed at the Zoological Society's Gardens a year or two back: the young was observed to take both teats of the mother into its mouth at once. Mr. Sclater in a recent list of the group allows forty-seven species, of which thirty-three were examined by himself. Subsequently, however, the list has been reduced to forty by the same authority. One of the rarest species is C. stairsi, first described from a skin stripped from a specimen which lived for a short time at the Zoological Gardens.
The genus Cynocephalus (or Papio) includes the Baboons; and the scientific name indicates the Dog-like aspect of these animals, due to the projecting snout. Cynocephalus is confined to Africa and Arabia. Several of the species of the genus are well known. The Mandrill, C. mormon (or maimon), has blue ridges on the muzzle, the bridge of the nose being red. The animal lives in herds, and is ferocious and omnivorous. The Chacma Baboon, C. porcarius, is the largest of Baboons. It lives in South Africa in large herds. The Arabian Baboon, C. hamadryas, is the Sacred Baboon of the Egyptians. The names of two other species, C. thoth and C. anubis, serve also to remind us of the ancient Egyptians. There are altogether eleven species of Cynocephalus.
Gelada (or Theropithecus) is separated as a distinct genus. Though regarded as a Baboon, Garrod has pointed out many points of likeness to Cercopithecus. The two species are, like the other Baboons, African.
Cynopithecus niger is a small black Baboon from Celebes. It has swellings on the muzzle as in other Baboons, but differs from them in being a more amiable creature as well as in its smaller size. It has a rudimentary tail, smaller even than the small tail of the typical Baboons. It has, like them, ischial callosities.
In the second sub-family, Semnopithecinae, the following characters are distinctive:—All the Apes of this group are slender in form, with a long tail. There are no cheek pouches. The stomach is sacculated; it is divided into three portions. This is accompanied by an apparently more exclusively vegetarian diet than characterises other Apes, which mingle with their diet of fruit a large proportion of insects, eggs, etc.
Fig. 270.—Black Celebesian Ape. Cynopithecus niger. × 1⁄5.
The first with which we shall deal is Colobus, containing the Monkeys known as Guerezas. These creatures are entirely confined to the African continent, and they are arboreal in habit. It has been attempted to show that their affinities are more with the Platyrrhines than with the group in which they are really to be placed. In favour of regarding them as nearer akin to the American monkeys are only two facts of importance: the first is the practical absence of the thumb, which of course recalls the condition characteristic of Ateles; in the second place, the nostrils in their wideness somewhat resemble those of the Platyrrhines. They are slender Monkeys with well-marked callosities. They have a complex sacculated stomach, resembling the large intestine of some other animals; it is not divided into distinct chambers like the stomach of a Ruminant or of a Whale. Correlated apparently with this large stomach is the small development of the cheek pouches. This genus, of which there are about ten species, is characterised by beautiful skins, which are largely collected. The Arabs have a legend to the effect that one species, when wounded, and seeing its capture and the removal of its skin inevitable, carefully tears the latter, that its captors may not profit by it. The species of this genus are most abundant on the west coast of Africa. It is interesting that one species, C. kirki, is limited to the Island of Zanzibar, where, however, it is nearly extinct.
The "Holy Apes," or Langurs, genus Semnopithecus, are allied to the last, but they are Asiatic in range. The thumb is better developed, but still shorter than in other Cercopithecidae; the callosities are small, and the cheek pouches are absent. There is a single large laryngeal sac, and the stomach is complex.
This genus is, like the Tiger, often quoted as an example of a race supposed to be characteristically tropical, existing habitually in the coldest climate. A species of Semnopithecus has been observed climbing snow-laden branches at a height of 11,000 feet in the Himalayas. There are some thirty species, which extend as far east as Borneo.
Fig. 271.—Entellus Monkey or Hanuman. Semnopithecus entellus. × 1⁄6.
The name Semnopithecus is derived from the fact that the Hanuman is regarded as sacred by the Hindus. The best-known species of Semnopithecus is this Langur or Hanuman, S. entellus. Being regarded as a sacred animal, and with the advantage thus gained, it has become a fell nuisance in gardens and to crops. Though the veneration with which the Hindoos regard these animals will not allow them to slay them, they are exceedingly thankful to a European who will enable them to commit a sin vicariously. This Ape has immense powers of leaping—a space of 20 to 30 feet can be cleared by them if one side, that from which the leap is taken, be considerably higher than the other. They are useful to the Tiger hunter, as they follow and hoot at this, their deadly enemy. S. schistaceus is a species which lives at great heights, not less than 5000 feet, in the Himalayas.
The genus Nasalis is hardly separable from the genus Semnopithecus. It is a Bornean animal, and is distinguished by a comical long nose, which not only suggests, but goes beyond, the aquiline nose of the human species. It is no doubt on this account that the Borneans, unconsciously imitating our habit of comparing "natives" in general to Monkeys, call it by a name which signifies "white man." Rhinopithecus has also a long, but a more definitely upturned nose.
Fossil Monkeys.—Several of the existing genera of Old-World Apes are also known to have existed in past times; in some cases their past distribution indicates a greater range. Thus Macacus is now represented—and that doubtfully—in Europe by the Barbary Ape alone. But from Montpellier have been unearthed the remains of M. priscus, from Pliocene beds. The Asiatic Semnopithecus is known to have lived during the Pliocene period; its remains are discovered in France and Italy, as well as in Asia. In addition to these existing forms, a number of totally extinct Old-World genera are known. The rich formation at Pikermi near Athens has produced Mesopithecus pentelici; this Monkey has a skull which recalls that of Semnopithecus, while the stout limbs are rather Macaque-like. As is the case with many living Catarrhines, the males have stronger canines. The animal had a long tail.
An analogous annectent character is shown by the Italian fossil, Oreopithecus bambolii. This animal was referred by one palaeontologist to the Man-like Apes, by another to the Cercopithecidae. It suggests a common ancestral form, and is Middle Miocene in horizon.
Just as there are no Platyrrhine Apes in the Old World so there are no Catarrhines met with in a fossil condition in the New World; the two great divisions of the Apes were as distinct in the past, so far as we know, as they are now—a strong argument in favour of those who would derive them from two sources. The existing genera, Cebus, Mycetes, and Callithrix, now living in South America, are also known in a fossil state. The extinct genus Homunculus is known from the Tertiary strata of Patagonia, and an apparently allied form is Anthropops. These creatures, however, are at present far from exhaustively known.
Fam. 2. Simiidae.—The Anthropoid, or Man-like Apes, may be separated from the lower Apes as a group, Simiae, or perhaps better, on account of the after all slender points of difference, a family Simiidae, which has the following distinctive characters.
Though arboreal creatures for the most part, these Apes, when they come to the ground, progress in at least a semi-erect fashion. Moreover, when they, as is usually the case, put their hands upon the ground to aid in walking, they do not rest as do the lower Apes upon the flat of the hand, but upon the back of the fingers. None of the Anthropoids has a tail, or cheek pouches. Ischial callosities are only seen in the Gibbons. There is commonly a laryngeal pouch, which is of large size, and aids in the production of the generally loud voice of these creatures. The hair is rather more scanty than in the Cercopithecidae, which is an approach to Man. The placenta differs in detail from that of the lower Apes, and is exactly like that of Man. These Apes show as further differences from the underlying Cercopithecidae, the greater length of the arms as compared with the legs, and the presence of a vermiform appendix to the caecum. In the latter but not the former character they agree with Man, whom we shall place in a separate family, Hominidae. The Anthropoid Apes are entirely Old World and intratropical in range at the present time.
The Gibbons, genus Hylobates, stand quite at the base of the series of existing Anthropoid Apes. They are the smallest and the most purely tree-frequenting of all the members of that group. Connected with this habit is the structural peculiarity that their arms are proportionately longer than in the other Anthropoids. The affinity of the Gibbons to the Catarrhines is proved by the presence of distinct but small ischial callosities. The arms are so long that when walking upright the hands reach the ground. The hallux is well developed. The ribs are thirteen pairs. In the skull the chief noteworthy character as compared with other Anthropoids is the fact of the large size of the canines, which are of equal or nearly equal size in the two sexes. The molars on the other hand have been particularly compared to those of Man. The brain is simpler than in the higher forms. But it is not clear that this may not be a case of diminished complexity of convolution going hand in hand with smallness of size.
Fig. 272.—Hoolock. Hylobates hoolock. × 1⁄6.
The Gibbons range through south-eastern Asia from Assam and Burmah to Hainan. The number of species is a little doubtful. It is clear that in the first place we may distinguish the Siamang, H. syndactylus, which indeed some regard as a separate genus. It is mainly to be defined by the syndactylous character of the second and third toes; they are united by skin as far as the last joint. The Hainan species, H. hainanus, is probably distinct, and the following names have been given to various other species or races, viz. H. agilis, H. leuciscus, H. leucogenys, H. lar, H. hoolock. These animals can walk erect; and when they do so, the big toe is separated as in unsophisticated or at least unbooted man. The voice is well known to be loud, and it is a curious fact that the Siamang, which has a large laryngeal pouch, is not excelled in this respect by species in which this sac is not developed.
Fig. 273.—Cerebrum of the Gibbon (Hylobates). (Lateral aspect.) c.c′, c.c″, Anterior and posterior central convolution; fi, interparietal fissure; fr, frontal lobe; f.s, Sylvian fissure; oc, occipital lobe; pa, parietal lobe; s.c, fissure of Rolando; tp, temporal lobe; *, fronto-orbital fissure. (From Wiedersheim's Structure of Man.)
Of Gorillas, genus Gorilla, there is but one species, which must apparently and rather unfortunately be called Gorilla gorilla.
The misfortune is double: in the first place the repetition of the same word as both generic and specific appellation is tiresome to the ears and barbarous in its suggestion; in the second place it is now well known that the "Gorilla" of Hanno, observed by that Carthaginian voyager on an island off the African coast, was not a Gorilla at all as the word is now understood, but probably a Baboon. The external aspect of this great Anthropoid is familiar from many reproductions. The male, as is usual, is larger than the female, and his characters are more pronounced.
The face is naked and black, and the skin generally is deep black, even at birth. The ear is comparatively small, and is adpressed to the side of the head; it is altogether more human in form than that of the Chimpanzee, and this statement applies also to the rudimentary condition of the muscles of the ear, which are more rudimentary than in the Chimpanzee. The nose has an obvious median ridge, and is thus pronounced as an external feature; the nostrils are very wide. The hands and feet are short, thick, and broad; the digits are webbed. In the foot the heel is more apparent than in other Anthropoids. It is not, however, so marked as in Man, and the phrase "Ex pede Herculem" has been aptly supplemented by "Ex calce hominem." The hair upon the head forms a kind of crest, which can be elevated when the animal is enraged. The neck is thick and short, and the beast has massive shoulders and a broad chest.
Fig. 274.—Gorilla. Gorilla gorilla, ♀. × ⅛.
If it were not for the fewness of the Anthropoid Apes, and their nearness to Man, it is doubtful whether the Gorilla would be ranked as a distinct genus, for in internal structure it is very near the Chimpanzee. The microscopic character of the investigations into the anatomy of Man have somewhat dimmed the proper sense of perspective, and have tended to throw into greater prominence than seems necessary the divergences of structure seen in the Gorilla. Dr. Keith has recently summed up and commented upon these divergences, and the following account of this Anthropoid is mainly deduced from his memoir.
The cranial capacity of the Gorilla is greater than that of the Chimpanzee. It is not possible, however, to decide from this point of view whether a given skull is that of one or of the other of these Apes. Some Chimpanzees are higher in capacity than some Gorillas. But the average is undoubtedly as stated. It is to be noted that there is a correspondence between cranial capacity and size of palate, the correspondence being converse, i.e. the greater the brain the smaller the palate. This applies to Man as compared with his Ape-like relatives, but does not apply so accurately to the Gorilla, which has a more extensive palate than the Chimpanzee; its "brute development" is much greater than that of the Chimpanzee. Not only is the palate larger, but the molar teeth, slightly different in form, are also larger and stronger. This is so plainly marked that "one may say almost with certainty, that any upper molar tooth over 12 mm. in length is that of a Gorilla, and under 12 mm. is that of a Chimpanzee." In the skeleton generally it may be said that the crests for muscular attachments upon the bones are greater in the Gorilla. The nasal bones are more like those of lower Apes in their length, and they have a sharp ridge more marked than in the Chimpanzee, which, however, disappears in aged animals. It is a curious fact that Gorillas often have a "cleft palate," owing to the failure of the palatal part of the palatine bones to meet completely. The general conformation of the skull is less brachycephalic in the Gorilla.
The limbs show a number of small differences, which are associated with a more completely arboreal life in the Chimpanzee as compared with the Gorilla. The latter is approaching the human way of life. In spite, however, of these differences, no hard and fast lines of divergence can be laid down between the two African Anthropoids, for it appears from the many memoirs that have been written upon both that "there is scarcely a feature in any muscle or bone found in one animal which is not also found in the other." The heel of the Gorilla has already been referred to. This is, of course, associated with a plantigrade and therefore non-arboreal mode of progression. Certain of the muscles of the calf of the leg attached to the heel show a more human arrangement in the Gorilla than in the Chimpanzee. It is interesting to find that the muscles of the little toe are diminishing in the Gorilla as in Man. This is most clearly due to terrestrial progression and we may apply the same explanation to Man and ignore tight boots! The arm of the Gorilla is less adapted to arboreal progression. Its proportions differ from those of the arm of the Chimpanzee in that the fore-arm is shorter. In both animals the thumb is not of much use, and this digit is more retrograde in the Gorilla, not only in proportionate length but in its muscular supply. The hip girdle tells the same tale. It is broader in the Gorilla, and the glutaei muscles are more prominent, all these features being connected with the more erect gait.
The brain of both animals have been studied, but not in the case of the Gorilla from a sufficiently large number of examples to make any generalisations of great value. On the whole, the Gorilla has the larger brain, but this must be discounted by the fact that it also has the larger body. It is a remarkable fact that the Gorilla's liver is much more like that of lower Apes than the liver of other Anthropoids. It has, as has the Chimpanzee, laryngeal sacs. The general conclusion concerning the relative position of the two African Anthropoids seems to be that the Gorilla is the more primitive; and as thus it must approach more nearly to the original parent than does the Chimpanzee, it may be said that it also comes rather nearer to Man, since the Chimpanzee has travelled away from the common stock on another line. The detailed likenesses to Man, however, are not to be unduly dwelt upon; for they mainly come from a tendency to assume the plantigrade mode of progression.
In mental characteristics there is the widest difference between the two Apes that we are considering. The Chimpanzee is lively, and—at least when young—teachable and tameable. The Gorilla, on the other hand, is gloomy and ferocious, and quite untameable. When angry the Gorilla beats its breast, a statement that was originally made, we believe, by M. du Chaillu, but which has been disputed, though it appears to be perfectly true. A young Gorilla, exhibited some time since in the Gardens of the Zoological Society, could be observed to do so. The cry of the Chimpanzee is different from the "howl" of the Gorilla. An immense amount has been written upon the ways of this animal in its own home, including much that is legendary. The Gorilla has been said to lurk in the depths of the forest, and to stretch down a prehensile foot to grasp and strangle an unfortunate black man passing below. It is said, too, to vanquish the Elephant by hitting it hard upon the trunk with a stout stick, and to crumple up the barrel of a rifle with its powerful teeth.
Apart from the doubtful "Pongo" and "Engeco" of Andrew Battel, our first intelligence concerning the Gorilla is due to Dr. Savage, after whom, indeed, the late Sir Richard Owen called the animal Troglodytes savagei, a name which has to be abandoned in favour of an earlier name.
The Gorilla is limited in its distribution to the forest tract of the Gaboon. It goes about in families, with but one adult male, who later has to dispute his position as leader of the band with another male, whom he kills or drives away, or by whom he is killed or driven away. The animal is said to make a nest in a tree like the Orang; but this statement has been questioned.
It feeds upon the berries of various plants, and upon other vegetable substances; there is apparently not so marked an inclination for animal food as is exhibited by the Chimpanzee. In search of their food they wander through the forest, walking partly upon the bent hand, and progressing with a shuffling gait. It is noteworthy that the Gorilla has been said to walk upon the palm of the hand and not upon the back, as is the case with the Chimpanzee. It can readily assume the upright posture, and, in this case, balances itself largely with its arms. Professor Hartmann, however, states that the back of the hand is also used. Unlike most or many wild beasts, the Gorilla exhibits no desire to run away when he views a human enemy. Dr. Savage remarks that "when the male is first seen, he gives a terrific yell, that resounds far and wide through the forest, something like kh-ah! kh-ah! prolonged and shrill." This is accompanied by offensive tactics, which the natives do not willingly encounter. When making an attack the Gorilla rises to his feet, and as a full-grown animal reaches a height of some five feet, he is a most formidable antagonist. The attack of one of these animals is said to be made with the hand, with which he strikes his adversary to the ground, and then uses the powerful canines. The beating of the breast which heralds an attack is a statement made by M. du Chaillu. It has been denied with a vigour and asperity quite incommensurate with the importance of the matter.
Fig. 275.—A, Cerebrum of a female Chimpanzee two years old. × ½. (Dorsal aspect, showing asymmetrical development.) c.c′, c.c″, Anterior and posterior central convolutions; f.i, interparietal fissure; f.l, the longitudinal fissure; f.po, parieto-occipital fissure; fr, frontal lobes; oc, occipital lobes; s.c, sulcus centralis. B, Brain of a female Chimpanzee two years old. × ½. (Lateral aspect.) cb, Cerebellum; c.c′, c.c″, anterior and posterior central convolutions; fr, frontal lobe; f.s, fissura Sylvii; is, island of Reil; md, medulla oblongata; oc, occipital lobe; pa, parietal lobe; s.c, sulcus centralis; tp, temporal lobe. (From Wiedersheim's Structure of Man.)
The Chimpanzees, genus Anthropopithecus (or Troglodytes), are to be distinguished from the Gorilla by the characters mentioned in the account of the latter animal. Briefly summed up they are mainly as follows:—The ears are large, and generally stand out from the head; but there are exceptions to be noted presently. The pigmentation of the body is not always so pronounced as in the Gorilla. The nasal bones are shorter. The skull as a whole is more brachycephalic, and the molar teeth are smaller. The hands and feet are much longer, the animal being more purely arboreal than the Gorilla. The female Chimpanzee is slightly smaller than the male, but the great disparity observable in the Gorilla does not characterise its ally. The animal, like the Gorilla, has large air sacs.
Fig. 276.—Skull of Chimpanzee. Anthropopithecus troglodytes. × ⅓. (After de Blainville.)
Chimpanzees are entirely restricted to Africa, and though they appear to extend rather farther east than the Gorilla, the forest-clad region of the equatorial belt is their home.
It has been mentioned in treating of the Gorilla that the main feature of this animal, which affords a constant difference from the Chimpanzee, is its gloomy and ferocious manner. The Chimpanzee, on the other hand, is lively and playful, though often maliciously so, and quite tameable, as many instances—particularly the notorious "Sally" of the Zoological Gardens—show. The earliest mention of animals that are probably Chimpanzees is to be found in a work upon the Kingdom of Congo, published in 1598. In a cut illustrating that work, and of which a part is reproduced in Professor Huxley's essay referred to below, the Apes, which correspond roughly in their appearance to Chimpanzees, are represented as being captured by the device of limed boots, which the Apes are putting on. This idea has been subsequently imitated and acted upon. A little later, Andrew Battel wrote of the Pongo and of another creature the Engeco. This latter, whatever may be the case with the former, is in all probability the Chimpanzee, since the word 'Nchego, now applied to those creatures, seems to be the same word. From this seems also to be derived the sailor's term "Jacko." Whether there are or are not more than one species of Chimpanzee, is a matter which has exercised and perplexed naturalists. That there are plain differences of external features, at any rate between individuals, is perfectly clear. We are justified in recognising three forms, but the question of their specific distinctness may for the present be held in reserve. The commonest of these is the variety known as A. troglodytes. This is frequent in menageries, though the specimens on view are nearly always young and small. The face and the hands are flesh-coloured, and the ears are very large. The black hair gets a reddish tinge on the flanks. The second variety is that which was termed by du Chaillu Troglodytes kooloo-kamba. This animal appears to be also the T. aubryi of MM. Gratiolet and Alix, and to be identical with two Apes known by the names of "Mafuca" and "Johanna." The former of these was exhibited in Dresden, the latter at Messrs. Barnum and Bailey's show. The two animals have been carefully studied. They differ from the common Chimpanzee by the dark colour of the face, and in the case of Mafuca the ear was Gorilline in form. So too was the ear of A. aubryi, while Johanna has a larger one. These features have led to the suggestion that the Kooloo-kamba was the result of a mésalliance between a Gorilla and a common Chimpanzee.
It has at any rate been stated that the two Anthropoids do go about in company; but there seems to be little doubt that there is no question here of a hybrid. Dr. Keith's careful studies upon Johanna have demonstrated the impossibility of regarding this Ape as anything but a Chimpanzee. The animal has the ways and manners of the Chimpanzee; has a cry exactly like that of A. troglodytes; does not beat her breast like a Gorilla when annoyed. Anatomical knowledge, however, of this specimen is at present wanting.
Fig. 277.—Young Orang-Utan. Simia satyrus. Zeitschrift für Ethnologie (Anthropolog. Gesellschaft), Bd. viii. (From Wiedersheim's Structure of Man.)
Anthropopithecus calvus seems to be at least as much entitled to distinction as the last. It was originally described by du Chaillu; but Dr. Gray who examined the skins thought that the baldness was accidental, and then after this wise caution proceeded to describe, under the name of A. vellerosus, perhaps the "worst" species of Chimpanzee that has been added to the unnecessarily long list of "species" of Chimpanzees. To this variety belonged "Sally" of the Zoo, whose intelligence has been celebrated by the late Dr. Romanes. The form is characterised by its intense blackness, the red reflection of other Chimpanzees not being visible; also by the bald head, whence of course the name. The nostrils of this Ape, as of Johanna, were somewhat expanded, and thus present a certain likeness to the Gorilla. But there can be no suggestion that A. calvus is the product of a union between the two African Anthropoids. As is the case with Johanna, Sally was given and enjoyed animal food on occasions. It is a curious fact that both Sally and Johanna appear to have been colour-blind.
Fig. 278.—Young Orang-Utan. Simia satyrus. Zeitschrift für Ethnologie (Anthropolog. Gesellschaft), Bd. viii. (From Wiedersheim's Structure of Man.)
The Orang Utan, genus Simia, has but one definable species, viz. S. satyrus. The supposed species of Owen, S. morio, cannot be satisfactorily defined. Plenty of other specific names have also been given to what is in all probability but a single species of large Anthropoid Ape inhabiting the islands of Borneo and Sumatra.
Fig. 279.—Skeleton of Orang. Simia satyrus. (After de Blainville.)
The name Orang-Utan, now applied exclusively to the subject of the present description, was formerly applied also to the Chimpanzee, and to that animal, moreover, under the latinised version of Homo sylvestris. The Orang is a large and heavy Ape with a particularly protuberant belly and a melancholy expression. The face of the old male is broadened by a kind of callous expansion of naked skin at the sides. The colour of the animal is a yellow brown, varying in the exact shade. The ears are particularly small and graceful in appearance, pressed closely to the sides of the head. The head is very brachycephalic. The arms are very long, and when the animal is in the erect posture they reach as far as the ankle. The hallux is very short and usually destitute of a nail. It is a curious fact that the head of the thigh bone is unattached by a ligament to the socket of the pelvis in which it articulates, a state of affairs which may give the limb greater freedom in movement, but does not add to its strength; indeed, the Orang has been described as moving with laborious caution.
This Ape inhabits flat and forest-clad ground, and lives mainly in the trees. The male leads a solitary life except at the pairing season, but the female goes about with her family. On the ground the Orang walks with no great ease, and uses his arms as crutches to swing the body along. Even on trees the rate of progress is not rapid, and is accomplished with careful investigations as to the capabilities of the branches to bear his weight. The "Man of the Woods" has been stated to build a hut in trees. This is an exaggeration of the fact that it constructs a temporary nest.
Fig. 280.—A, Skull of a young Orang-Utan. Simia satyrus. (One-third natural size.) B, Skull of an adult Orang-Utan. (One-third natural size.) (From Wiedersheim's Structure of Man.)
One of these nests has lately been described elaborately by Dr. Moebius. It was found (by Dr. Selenka) on the fork of a tree at a height of 11 metres from the ground. Every night, as it appears, or every second night, the animal constructs a new nest for himself, abandoning the old one. So numerous, therefore, are these nests in localities frequented by Orangs, that a dozen can be readily found in a day. The particular nest which Dr. Moebius examined was 1.42 metres long, and at most .80 metre broad. It was built of about twenty-five branches, broken off and laid for the most part parallel to each other. Above this framework a number of loose leaves lay. There is no doubt, therefore, that these nests are not by any means elaborate structures, and that they only serve as sleeping-places, and not as nurseries for the upbringing of the young, as has been asserted.
The Orang seems to be usually of a fairly mild disposition; it will rarely attack a man unprovoked. But Dr. Wallace, who has accumulated a large number of observations upon these animals, describes a female Orang who "on a durian tree kept up for at least ten minutes a continuous shower of branches, and of the heavy-spined fruits as large as 32-pounders, which most effectually kept us clear of the tree she was on. She could be seen breaking them off and throwing them down with every appearance of rage, uttering at intervals a loud pumping grunt, and evidently meaning mischief." The name given by the Dyaks to the Orang is Mias Pappan.
Fossil Anthropoid Apes.—Undoubtedly the most interesting of fossil Anthropoids is the now famous Pithecanthropus erectus. Our knowledge of it is due in the first place to Dubois. But there is hardly an anatomist or an anthropologist who has not had his say upon this regrettably very incomplete remnant. The creature is only known by a calvarium, two separate teeth, and a femur. And the femur, moreover, is diseased. M. Dubois discovered these remains in the island of Java in andesite tufa of Pliocene or at least early Pleistocene age. The remains were found in company with Stegodon, which is now extinct, and Hippopotamus, which is no longer found in that part of the world. The name Pithecanthropus was given to it by the discoverer in order to furnish with a definite habitation and a name the theoretical Pithecanthropus of Haeckel. Even the most particular of students of mammalian nomenclature will hardly object to the utilisation of a name for a second time which is with some clearness a nomen nudum! The animal when erect must have stood 5 feet 6 inches high. The contents of the cranium must have been 1000 cm., that is to say 400 cm. more than the cranial capacity of any Anthropoid Ape, and quite as great as or even a trifle greater than the cranial capacity of some female Australians and Veddahs. But as these latter are not 5 feet in height, the Ape-like man had really a less capacious cerebral cavity. The skull in its profile outline stands roughly midway between that of a young Chimpanzee (young in order to do away with the secondary modifications caused by the crest) and the lowest human skull, that of Neanderthal Man. This creature is truly, as Professor Haeckel put it, "the long searched for 'missing link,'" in other words represents "the commencement of humanity."
The remains of Apes, more distinctly Apes than Pithecanthropus, are known from Miocene strata of France. Two genera, Pliopithecus and Dryopithecus, are known. The former appears to be close to Hylobates. Dryopithecus is more Man-like than any other, and seems to have been as large as a Chimpanzee. The incisors are human in their relatively small size. But it has been pointed out that the long and narrow symphysis of the lower jaw is a point of likeness to the Cercopithecidae.
Fam. 3. Hominidae.—Apart from Pithecanthropus, which perhaps is a member of this family, but whose remains permit us to leave it among the Simiidae, at least for the present, the family Hominidae contains but one genus, Homo, and probably but one species, H. sapiens. The characters of the family may therefore be merged in those of the genus.
Though it is easy enough to distinguish a Man from an Ape, it is by no means easy to find absolutely distinctive characters which are other than "relative." As Professor Haeckel has pointed out, there are really only four characters which differentiate Man: these are the erect walk, and the consequent modification of the fore- and hind-limbs to that position; the existence of articulate speech; the faculty of reason. Whether one body of psychologists are right who argue that reason is a distinctive human attribute, not to be confused with the apparent reasoning powers of lower animals, or whether others are justified in separating Man only in degree from the lower animals, it is clear that this very diversity of opinion prevents us for the present from utilising such characters as absolute differences. In any case the discussion of these matters is beyond the scope of the present book.
Fig. 281.—Skull of Immanuel Kant. (After C. von Kupffer.) The great size of the cranium is a noteworthy feature. (From Wiedersheim's Structure of Man.)
Anatomically there are a number of small points which distinguish Man; but they are mainly due to the erect gait. It is sometimes attempted to divide Man as a naked animal. But this is an apparent difference only; the hair is not so much developed upon the body as in the Apes, save in occasional abnormalities, such as the various hairy men and women who can be seen in travelling shows, and to a less extent the Japanese Ainos, but it is present everywhere, as is shown by microscopical investigation of the skin. The skull in Man "is a smooth and imposing, rounded or oval bony case," which contrasts with the smaller and deeply ridged skull of the Anthropoid Apes. The shape of the skull is largely in accord with the large brain. The face does not project so much as in the Anthropoid Apes, though this character must not be insisted upon too strongly, as in some American Monkeys the face is as little projecting. Still we are now comparing Man with his undoubtedly nearest relatives the Simiidae. In the lower jaw the anterior line at the symphysis is an approximately straight one, that is at right angles to the long axis of the jaw, while Apes have a more retreating chin. The "beautiful sigmoid curve formed by the lumbar and dorsal vertebrae" is more pronounced in Man, but exists not only in the Anthropoids, but in other Apes.
Fig. 282.—Foot of Man, Gorilla, and Orang of the same absolute length, to show the difference in proportions. The line a′a′ indicates the boundary between the tarsus and metatarsus; b′b′, that between the latter and the proximal phalanges; and c′c′ bounds the ends of the distal phalanges. as, Astragalus; ca, calcaneum; sc, scaphoid. (After Huxley.)
Fig. 283.—Skeleton of the left pes of a Chimpanzee. (Dorsal aspect.) as, Astragalus; cb, cuboid; cl, calcaneum; ec, ectocuneiform; en, endocuneiform; ms, mesocuneiform; nv, navicular; I-V, digits. (From Wiedersheim's Structure of Man.)
The fore-limbs are relatively short, the extreme length of the arm being such that the outstretched hand does not reach the knee. The thumb is a large and useful digit in Man, much more so than in the Anthropoids. On the other hand the hallux is not opposable. This is, of course, correlated with the upright attitude, as is also the greater relative thickness of that digit, upon which the greatest stress is laid in walking. As to muscles, the glutaeus maximus is more developed in Man—the Ape which most nearly approaches him being the Gorilla, in which animal the life is less thoroughly arboreal than in some others. The so-called "scansorius" is only present in Man as an occasional occurrence. The rudimentary character of the ear muscles for the movement of the external ear in Man has often been insisted upon, as also their occasional functional activity. But here and elsewhere, so numerous are the abnormalities, that "the gap which usually separates the muscular system of Man from that of the Anthropoids appears to be completely bridged over." These are words of Professor Wiedersheim quoted from Testut, and express a final summary of the matter of muscles in Man and the Apes.
Fig. 284.—The hard palate, A, of a Caucasian; B, of a Negro; C, of an adult Orang-Utan, showing the differences in shape of the bones. The palate of the Negro represents a type transitional between that of the Caucasian and that of the Orang. mx, Maxilla; pl, palatine; p.mx, premaxilla. (From Wiedersheim's Structure of Man.)
In his teeth Man differs by the small exaggeration of the canines, which hardly, if at all, differ in the two sexes. There is also a complete absence of a diastema. The teeth are also on the whole weaker than in the Anthropoids, though Hylobates is very human in this particular.
Fig. 285.—Human Larynx in frontal section. cr, Cricoid cartilage; sn, sinus of Morgagni; t.c, first tracheal cartilage; th, thyroid cartilage. (From Wiedersheim's Structure of Man.)
There is a tendency in Man towards the disappearance of the upper outer incisors, and more markedly still of the wisdom teeth, which appear very late, and are often imperfect. In a large number of cases the tooth does not appear at all. In the larynx there is no great development of the great throat pouches of the Anthropoids. The minute diverticula of that organ, known to human anatomists as the ventricles of Morgagni, alone remain to testify to a former howling apparatus in the ancestors of Man.
- 389 ^ For a general account of the Primates, see Forbes in Allen's Naturalists' Library, London, 1894.
- 390 ^ See Dr. Mivart's papers in Proc. Zool. Soc. 1864, -65, -66, -67, and -73 for osteology and teeth.
- 391 ^ Murie and Mivart, Trans. Zool. Soc. vii. 1869, p. 1.
- 392 ^ Trans. Zool. Soc. v. 1863, p. 103.
- 393 ^ Hist. Nat. de Madagascar, Mamm. 1875.
- 394 ^ Proc. Zool. Soc. 1895, p. 142.
- 395 ^ Trans. Zool. Soc. v. 1863, p. 33.
- 396 ^ Verh. Ak. Amsterdam, xxvii. 1890, Art. 2.
- 397 ^ "On some Points in the Structure of Hapalemur griseus" Proc. Zool. Soc. 1884, p. 301.
- 398 ^ Beddard, Proc. Zool. Soc. 1900, p. 661.
- 399 ^ On the Arm Glands of the Lemurs, Proc. Zool. Soc. 1887, p. 369.
- 400 ^ So at least the formula has been given; but it is very possible that the supposed second incisor is really, judging from the other Lemurs, a canine.
- 401 ^ The Malagasy, however, must be vague in definition, or their interpreters not well grounded in the rudiments of the language; for Sonnerat states that Indri signifies "homme des bois."
- 402 ^ Syn. Microrhynchus.
- 403 ^ Beddard, Proc. Zool. Soc. 1884, p. 391, and 1891, p. 449; and Jentink, Notes Leyd. Mus. 1885, p. 33.
- 404 ^ Proc. Zool. Soc. 1899, p. 554.
- 405 ^ Royal Natural History, London, 1894, p. 211.
- 406 ^ See Novitates Zoologicae, vol. i. 1894, p. 2.
- 407 ^ Proc. Zool. Soc. 1900, p. 321.
- 408 ^ "On the Angwantibo," Proc. Zool. Soc. 1864, p. 314.
- 409 ^ Verh. Ak. Amsterdam, xxvii. 1890.
- 410 ^ Proc. Zool. Soc. 1882, p. 639; see also Rev. G. A. Shaw, Proc. Zool. Soc. 1883, p. 44, 2nd Art.
- 411 ^ For a survey of the position of Tarsius, see Earle, Amer. Naturalist, xxxi. 1897, p. 569; and Nat. Science, x. 1897, p. 309.
- 412 ^ See Schlosser, Beiträge Pal. Osterr. Hung. 1888; also Osborn and Earle, Bull. Amer. Mus. Nat. Hist. vii. 1895, p. 16.
- 413 ^ Proc. Zool. Soc. 1899, p. 987.
- 414 ^ Phil. Trans. clxxxv. B, 1894, p. 15.
- 415 ^ It seems to be possible that this great Lemur was extant so lately as 1658, when a creature possibly answering to it was described by de Flacourt.
- 416 ^ "Notes on Callithrix gigot," Proc. Zool. Soc. 1884, p. 6.
- 417 ^ Forbes, Proc. Zool. Soc. 1880, p. 639.
- 418 ^ "On a new African Monkey of the genus Cercopithecus, with a List of the known Species," Proc. Zool. Soc. 1893, p. 243; see also p. 441.
- 419 ^ Proc. Zool. Soc. 1879, p. 451.
- 420 ^ See the books quoted on p. 576 (footnote).
- 421 ^ It is not so ranked by everybody.
- 422 ^ Proc. Zool. Soc. 1899, p. 296.
- 423 ^ For accounts of the habits of the Gorilla, compiled from various sources, see Hartmann's "Anthropoid Apes," International Scient. Ser. London, 1885; H. O. Forbes, "Monkeys," in Allen's Naturalists' Series, London, 1894; and Huxley, "Man's Place in Nature," vol. vii. of Collected Essays, London, 1894.
- 424 ^ "Man's Place in Nature," vol. vii. of Collected Essays, London, 1894.
- 425 ^ Hartmann's "Anthropoid Apes," in International Sci. Ser. London, 1885.
- 426 ^ Nouv. Arch. Mus. Hist. Nat. Paris, ii. 1866.
- 427 ^ Proc. Zool. Soc. 1899, p. 296.
- 428 ^ See also Duckworth, Proc. Zool. Soc. 1898, p. 989.
- 429 ^ For the structure of this Ape see Beddard, Trans. Zool. Soc. xiii. 1893, p. 177; and for experiments on her intelligence, Romanes, Proc. Zool. Soc. 1889, p. 316.
- 430 ^ For the external appearance of the Orang see Hermes, Zeitschr. f. Ethn. 1876, a paper which has coloured plates.
- 431 ^ Pithecanthropus erectus. Eine menschenähnliche Uebergangsform aus Java, Batavia, 1894. See also Ernst Haeckel, The Last Link (with notes by H. Gadow), London, 1898; Manouvrier, Amer. Journ. Sci. 1897, p. 213 (extracts); and Klaatsch, Zoolog. Centralbl. vi. 1899, p. 217.
- 432 ^ See especially Wiedersheim, The Structure of Man, transl. by Howes, London, 1895.
- 433 ^ Cunningham, "Cunningham Memoirs," No. II. Royal Irish Acad. 1886.