Cambridge Natural History Mammalia/Chapter XII
CETACEA—WHALES AND DOLPHINS
Order VI. CETACEA.
Aquatic Mammalia of fish-like form; tail expanded into horizontal flukes; a fatty dorsal "fin" present in most species; anterior limbs converted into fin-like paddles; posterior limbs only represented by skeletal rudiments. Hairy covering reduced to a few isolated hairs in the neighbourhood of the muzzle. Nostrils represented by the single or double blow-hole, nearly always situated far back upon the skull. Bones of loose texture and much impregnated with oil. The skull has a greatly-developed facial portion; supra-occipital bones meeting the frontal by overgrowing, or growing in between the parietals; bones surrounding the organ of hearing loosely attached to the skull, the tympanics of peculiar cowrie-shell form. Coronoid process of mandible absent, or very feebly developed. Teeth, when present, few or numerous, always of simple conical form, with at most traces of additional cusps (Inia); if absent their place taken by whalebone. Cervical vertebrae of short antero-posterior diameter, often more or less completely welded together into a single mass. Articulations between dorsal and other vertebrae feeble. Scapula peculiarly flattened; acromion strongly developed as a rule, but arising from a slightly-marked spine; coracoid process generally strongly developed. Phalanges of digits always more numerous than in other mammals. Clavicles absent. Stomach complex, consisting of at least four and often more chambers. Lungs simple and non-lobulated. Diaphragm obliquely set and very muscular. Brain much expanded transversely and well convoluted. Testes abdominal. Teats two, inguinal in position. Placenta diffuse and non-deciduate.
The Whales and Dolphins, which constitute this order, form an assemblage which is easily characterised by reason of the fact that their affinities to other groups of Mammalia are so doubtful that they furnish matter rather for speculation than for authoritative statement. Some hold that they resemble in certain points the Ungulata; while others again see in them the culminating term of a series which commences with such a form as the Otter, and of which the Seals and Sea-lions are intermediate stages. A third opinion is that the Whales have arisen from some low mammalian stock, too primitive to be assigned to any existing order of mammals. Palaeontology, as will be seen later, throws no light whatever upon their origin. This matter has already been referred to (see p. 120) in considering the position of the Cetacea.
The Whales include the most gigantic of all the orders of vertebrated animals. No creature living or extinct is so large as the Sibbald's Rorqual, which attains to a length of some 85 feet, or perhaps even rather more. On the other hand we have what are by comparison minute forms. Apart from the possibly problematical Delphinus minutus, stated to be only 2 feet in length, we have as a minimum 3 or 4 feet. The size of the Cetacea has been subjected to much exaggeration. The first duty of a Whale, observed the late Sir William Flower, is to be large; and Natural Historians, in the recent as well as in the remote past, have not hesitated to put very round numbers upon the dimensions of the larger members of the order. We may perhaps pass over Pliny's "fish called balaena or whirlpool, which is so long and broad as to take up more in length and breadth than two acres of ground," and a number of analogous exaggerations, which gradually dwindled down to the dimensions just stated of the great Rorqual. M. Pouchet has made the ingenious suggestion that the statements of the ancients may have been nearer the truth than observations of to-day would have us believe; he pointed out justly that in former times Whales were not so relentlessly pursued as during the last century; the inference being that they may have lived to a greater age, and attained a more colossal bulk. The more modern exaggerations in the dimensions of the bigger Whales are probably due to the fact that measurements have been taken, not in a straight line from snout to tail, but along the bulging sides of the Cetacean, rendered even more convex than in nature by decomposition, and by pressure due to the immense tonnage of the creature.
The Cetacea are the most perfectly aquatic of all mammals; they never leave the waters which they inhabit. It is true that legends have represented them as pasturing upon the shore—Aelian spoke of Dolphins basking in the sun's rays upon the sand; and the "Devil Fish" of California, Rhachianectes (see p. 357) has given rise to improbable stories—but they are apparently only legends. Indeed a stranded Whale cannot live long, for it is unable to breathe, the comparatively feeble breast being crushed by its own weight. In accordance with the purely aquatic habit, we find a modification of the outward form of the body (and as we shall see later of many of the internal organs), which renders the Cetacea externally unlike all other mammals. The form is fish-like, the fore-limbs are paddles, the tail is expanded into two horizontal flukes, which serve to propel the creature through the water.
Fig. 180.—Killer. Orca gladiator. × 1⁄40 (After True.)
The skin is smooth and shiny, so smooth and so shiny that it has often been compared to coach leather. But nevertheless they are not entirely without that most essential character of the class Mammalia, a coating of hair. The hairy covering is, however, reduced to the very smallest proportions; it is represented by a few hairs only—so few that they can be counted with ease—in the neighbourhood of the muzzle. These hairs are not present in all Whales; they are absent, for example, in the White Whale or Beluga. When present they are not furnished either with sebaceous glands or with muscular fibres, which are such universal concomitants of the hair follicles in the Mammalia generally. This appears to be conclusive evidence that the hairs, few as they are, are still undergoing degeneration. The need for a furry coat is removed by the presence of a thick coating of fat immediately underlying the skin. This is known as the blubber, and is the main incentive to the pursuit of Whales. It must not, however, be assumed without further argument that the hair is absent because its place is taken, as a mechanism for retaining the heat, by the blubber; for the Seal tribe possess both fur and blubber. Another conceivable explanation is quite at variance with such a view of economy. It may be noticed that among Ungulates there is a tendency to lose hair, particularly among more or less aquatic forms. Thus the Hippopotamus is almost naked (as is indeed the Walrus); the Rhinoceros, too, often a frequenter of marshy soil, is almost as denuded as is the Hippopotamus. It is not, however, settled that the Whales have anything to do with the Ungulata; otherwise an additional argument might be used, that is, the secular loss of hair in some members of this group. The Hairy Rhinoceros, Rh. tichorhinus, was, as its name denotes, a hairy beast; the Mammoth was equally so. The descendants, or at least the modern representatives of both these creatures, are but scantily clad with hairs.
A final reason for the naked character of the skin in existing Cetacea is closely connected with a feature in the organisation of three or four living species which must first be described.
Some years ago the late Dr. J. E. Gray of the British Museum described from the sea, off Margate, what he considered to be a new species of Porpoise, characterised by the presence on the dorsal fin of a row of stony tubercles. As a matter of fact it was subsequently shown that the Common Porpoise has the same structures, so that there was no need for a Margate species, Phocaena tuberculifera. Moreover, in the Indian Neomeris, a close ally of the Porpoise, a more abundant calcified covering of scales exists along the whole back of the animal. These plates, it has been discovered, are larger in the foetus, a fact which naturally points to their being an inheritance from the past, now undergoing retrogressive changes. Such a way of looking upon the facts is confirmed by the finding, many years ago, by the naturalist and physiologist Johannes Müller, of bony plates in connexion with the remains of a Zeuglodont Cetacean. It looks, therefore, very much as if the Eocene ancestors of the modern Cetacea had a skin studded with bony plates, as have the armadillos. This being the case, the disappearance of hair is not surprising. The room would be taken up by the calcified plates, and when the latter disappeared, as they have in the vast majority of existing Whales, the naked skin alone would be left.
Whales possess no externally-visible hind-limbs; rudiments of these appendages are present, which will be dealt with under the description of the principal features of the skeleton. But it has been discovered that in the Porpoise, external vestiges of hind-limbs do appear in the foetus, a fact which, be it observed, does away with the old view that the flukes of the Whale are the last term in the series of vanishing hind-limbs, of which the Seals, with their hind-limbs and tail bound up together, offer an intermediate step.
The tail is fish-like in form, but the flukes are horizontal instead of vertical as in fishes and Ichthyosaurus. This arrangement is no doubt associated with the need for rapid return to the surface waters after a prolonged immersion in search of food. A downward stroke, such as is given by the powerful and large tail flukes, would naturally bring about this result rapidly. The tail, moreover, is under all circumstances the swimming organ. Its motion has been stated to be slightly rotatory, like that of a screw, and it is the case that the two flukes are often alternate in shape like the flanges of a screw; one being convex upwards, the other convex downwards.
The fore-limbs are in the form of paddles, but they do not apparently serve as organs of locomotion so much as balancers. When a Whale is killed, it falls over on to one side, the office of the flippers being to maintain the proper position. It is believed, however, from the fact that the embryo often shows a relatively larger pectoral fin than that of the adult—the difference being due to a reduction in the adult of the number of phalanges—that the fin was once an organ of progression.
The pectoral fin of Whales exists in two forms. In the Toothed Whales it is shorter and rounder; in the Whalebone Whales longer and narrower. Structural differences accompany these outward dissimilarities. In the first-named group the humerus and the beginning of the radius and ulna are within the body, and do not form a part of the fin. In the Whalebone Whales, on the other hand, the fin contains all the bones of the fore-limb. Another remarkable contrast between the hand in the two groups of Whales is that while the Toothed Whales have five fingers, thus justifying the prevailing opinion that they are the more primitive of the two groups, the Whalebone Whales have only four fingers. Actually the Right Whale, Balaena, seems to have five fingers; and, indeed, the fact that it has, is often used to distinguish it from the Humpback, which has undoubtedly only four. But a careful consideration of the state of affairs which prevails in the foetus of Balaenoptera dispels this idea. Between what are apparently the second and third fingers, a rudimentary finger, consisting of four phalanges, appears. This is not produced, as is an additional finger found in the White Whale or Beluga, by a splitting of a finger. Accordingly the four-fingered condition of the Whalebone Whales is produced by the dropping out of a finger in the middle of the series,—a very remarkable fact. When fingers disappear, as, for instance, in the Horse, etc., it is at the two ends of the series that the digits vanish. If this view of Professor Kükenthal's be accepted, it follows that the presumed thumb of the Right Whale is what has been termed the prepollex.
The hand of the Whales, like those of some other aquatic creatures, e.g. the reptile Ichthyosaurus, has a larger number of phalanges than have terrestrial animals. The result of this is, of course, to increase the length of the fin and its utility as a paddle. It is commonly not all the fingers that have developed this great number of accessory phalanges. Rudimentary nails have been found upon the Cetacean hand; but in no case are they functionally developed. In the Manatees we have the disappearance of the nails still imperfectly accomplished. In M. latirostris there are nails; these have vanished, apart from possible traces to be seen with a microscope, in M. inunguis.
A very characteristic feature of certain Whales are the furrows to be seen on the throat. This is especially the case with the Rorquals, in which group the Humpback Whale, Megaptera, is to be included. The whales of these two genera (Balaenoptera and Megaptera) have a large number of the throat furrows—as many as sixty have been counted. Some other Whales have a smaller number; thus Rhachianectes has but two on each side, and the Physeteridae have not many more. These furrows are absent in very young embryos. It is thought by Professor Kükenthal that they allow of a wide opening of the mouth.
Fig. 181.—Dorsal surface of bones of right anterior limb of Round-headed Dolphin (Globicephalus melas). × 1⁄10. The shaded portions of the digits are cartilaginous. c, Cuneiform; H, humerus; l, lunar; R, radius; s, scaphoid; td, trapezoid or magnum; U, ulna; u, unciform; II-V, digits. (From Flower's Osteology.)
The blow-hole of Whales is, of course, the aperture of the nostrils, which are not so far back in the foetus as in the adult. By the characters of the nostrils the Toothed Whales can be distinguished from the Baleen Whales; in the latter the orifice is double, in the former single. In embryos of Dolphins, however, the two apertures are quite independent. The phenomena of spouting have often been misinterpreted. When the Whale breathes, the expired air rushes out through the nostrils. The water vapour in the breath condenses into drops of water in the cold Arctic regions where the phenomenon has been mainly observed. Hence the idea that water taken in at the mouth is expelled through the blow-hole. As the Whale approaches the surface to breathe, it may be that some of the water of the sea is driven upwards by the forcible expulsion of air from the lungs. But for the most part the water which is spouted is simply condensed breath.
Like some, but not all, other aquatic Mammalia the Whales have apparently no external ear. Indeed the opening of the ear is excessively small. In a huge Rorqual it will "admit a quill"; and although "a quill" is rather vague, we may fairly allow any sized quill without proving that the orifice of the auditory passage is anything but exceedingly minute. As a proof, added to so many, that the Whales are the progeny of terrestrial creatures, we have the occasional traces of external ears.
Fig. 182.—Left lower jaw of foetus of Balaenoptera rostrata. Inner aspect, natural size, showing teeth. (After Julin.)
Whalebone Whales never possess permanent teeth as well as the baleen; but in the foetus are more than traces of true teeth, which, however, never arrive at maturity. The whalebone itself is described later (p. 354). That the Whalebone Whales possess teeth while in the foetal condition was discovered so long ago as 1807. It has since been confirmed by many observers. Not only is there one set of teeth developed in the foetal Balaenoptera but two, of which one comes to a greater maturity; the other, in fact, remaining at a very early stage of development. The more complete dentition belongs to the milk series, as is the case with the Toothed Whales. A very interesting conclusion with regard to the derivation of the simple conical teeth of Whales seems to follow from the development of these structures in Balaenoptera. There are in the young foetus fewer teeth than in the more advanced embryo. Now in the younger embryo some of the teeth are furnished with more than one cusp; they are bi- or even tri-conodont. As Sir R. Owen observed, the teeth—some of them—are literally double teeth. This is a suggestion of the more complicated teeth of the Zeuglodonts, and shows so far that the simple conical teeth of existing Whales (cf. however the Platanistidae) are not by any manner of means so primitive as their actual structure would undoubtedly lead one to believe. Further than this, the greater number of teeth in the older embryo coincided with the disappearance of these double teeth, which seem to split up into the simple conical teeth.
The Toothed Whales are not furnished with baleen, but with teeth only. These teeth are more or less numerous, their arrangement being of value in the classification of the group; a matter which is dealt with later.
In the Narwhal, whose dentition in the adult is reduced to the well-known tusk or tusks (properly developed only in the male), there is a complete foetal dentition. A very curious fact has been elucidated by Professor Kükenthal about the dentition of the Common Porpoise. It appears that in this Cetacean the two teeth corresponding to each other of the two dentitions may fuse into a single tooth, which has in consequence a double crown. It may be that this is the case with the Platanistid Inia, and that its diconodont teeth are not, therefore, a reminiscence of the comparatively complicated teeth of the ancient Zeuglodonts.
The internal organs of Whales which show the greatest peculiarities as compared with other mammals are the stomach, the lungs, and the diaphragm. Whales always possess a complicated stomach divided into many, but into a variable number of, chambers: there are as few as four in some, as many as fourteen in Ziphioids.
On account of its complication the stomach has been compared to that of Ruminants—it has even been alleged that Whales "ruminate"—but the comparison will not hold good. Nor, on the other hand, is there a very close resemblance to the equally-complicated stomach of the Sirenians.
The Rorqual has a stomach with as few compartments as any. The only Whale which appears to have fewer is Balaena mysticetus, where there are but three. In the Rorqual the oesophagus opens into a more or less globular sac; from the upper end of this, i.e. close to the entry of the oesophagus, arises the second chamber, long and narrowish; then follows an extremely short third sac, then a larger fourth, after which comes the dilated commencement of the small intestine. The latter might be regarded as a chamber of the stomach were it not for the fact that the ducts of the liver and the pancreas open into it. This represents one type of the Cetacean stomach, which seems to be found in all Whales except the Ziphioids. In the latter, the oesophagus opens into the first compartment as usual; but the second division of the stomach arises not close to the entrance of the oesophagus, but at the opposite end. It would seem, therefore, as if the first division of the stomach, found in most Whales, were missing in Ziphioids. This way of looking at the matter is confirmed by the fact that in Hyperoodon a remnant of the missing first stomach is found in the shape of a small diverticulum of the oesophagus just before it enters the stomach.
The essential difference between the Whale's and the Ruminant's stomach is this: in the latter the stomach is primarily divided into two portions, of which the first is non-digestive and is clothed with oesophageal epithelium. The second, the abomasum, is the digestive region. The first part is again divided into three compartments. In the Whales, on the other hand, it is the digestive part which is again subdivided, while if the first part is divided it is not markedly so as in the Ruminants.
The lungs are remarkable for their unlobulated character; in this they agree with the lungs of the Sirenia. The thoracic cavity in which they lie is barrel-shaped, and not, as is usual in terrestrial mammals, boat-shaped, i.e. narrower sternally than above. The alteration of the shape of the thoracic cavity is associated with the aquatic life; so at any rate the fact that it is also marked in Seals and even in the Otter seems to show. The Whales are also characterised by the great obliquity of the diaphragm, which is extremely muscular. In this character again we find an agreement with the Sirenia, and also with other aquatic mammals; it is not therefore a character of Whales so much as evidence of an adaptation to the aquatic life. The advantage is, it appears, in the increased capacity of the thoracic cavity, and the consequent greater possibilities of expansion of the lungs, which it must be remembered serve as hydrostatic as well as breathing organs.
Some of the internal arteries of Whales break up into retia mirabilia. Their kidneys are lobulated; whether this has anything to do with the aquatic life is not so clear. It also characterises the Sirenia, more or less, and the Otters; but, on the other hand, the terrestrial Bears show the same structure as do also some Ungulates. It must be borne in mind, too, that the kidneys of foetal Man are lobulated.
The liver is a compact organ not showing such lobulation as is common, but not universal, among mammals.
The bones of Whales have a somewhat loose structure, and are much impregnated with oil. In many features the skeleton of Whales is highly distinctive of the order.
Fig. 183.—Skeleton of Porpoise (Phocoena communis), acr, Acromion process of scapula; cerv, united cervical vertebrae; chev, chevron bones; cor, coracoid process; hu, humerus; hy, hyoid; jug, jugal; lumb.trans, lumbar transverse processes; max, maxilla; nas, nasal; orb, orbit; par, parietal; pelv, vestige of pelvis; per.ot, periotic; pr.max, premaxilla; rad, radius; rb1, first rib; rb12, twelfth rib; sc, scapula; s.occ, supra-occipital; st, sternum; uln, ulna; zyg, prezygapophysis. (From Parker and Haswell's Zoology.)
The brain case is small proportionately and rounded. The "face" is therefore long, and in some cases, especially among the fossil forms of Platanistidae, the rostrum is extraordinarily elongated. The asymmetry of the Whale's skull is one of its most remarkable features; this, however, is entirely limited to the Toothed Whales, and among them is more pronounced in some forms than in others. Thus the Platanistidae and many Ziphioids are not nearly so asymmetrical as the Dolphins and, especially, Physeter. This asymmetry affects particularly the premaxillae, the maxillae, and the nasals. The base of the skull is symmetrical. The Whale's skull has very long premaxillae which, however, do not, except in the extinct
Fig. 184.—Under surface of the cranium of a young Caa'ing Whale (Globicephalus melas). × 1⁄5. AS, Alisphenoid; BO, basioccipital; cf, condylar foramen; ExO, exoccipital; Fr, supra-orbital process of frontal; gf, glenoid fossa of squamosal; Ma, body of malar; Mx, maxilla; OS, orbitosphenoid; Per, posterior (mastoid) process of periotic; Pl, palatine; PMx, premaxilla; Pt, pterygoid; Sq, squamosal; tg, deep groove on squamosal for meatus auditorius externus, leading to tympanic cavity; Ty, tympanic; Vo, vomer; ZM, zygomatic process of malar. (From Flower's Osteology.)
Zeuglodonts, bear any teeth. The nasal bones, whether symmetrical or the reverse, are very small in existing Whales, which arrangement, together with the long and broad maxillary bones, removes the anterior nostrils, the blow-hole, far backwards. The roof of the skull is not at all formed by the parietals externally. These bones form a portion of the side of the cranium, but are replaced or covered by the enormously-developed supra-occipital in the adult. Here again the Zeuglodonts are more typically Mammalian, for in them the parietals have a normal development and situation, rising even into a median crest as in so many quadrupeds. The bones related to the organ of hearing, the tympanis and petrous bones, are very solid and dense in structure. Moreover they are but loosely attached to surrounding bones, and are thus easily and frequently lost. Nearly the only mammals which resemble the Whales in the fact that the pterygoids sometimes meet in the middle line below are the Edentata (Anteater and Armadillo, see p. 167). But in both groups this peculiarity is not universal.
Fig. 185.—A section of a skull of a young Caa'ing Whale (Globicephalus melas). × 1⁄5. a, Angle; an, anterior nares; AS, alisphenoid; bh, basihyal; BO, basioccipital; BS, basispnenoid; cd, condyle; cp, coronoid process; ExO, exoccipital; Fr, frontal; id, inferior dental canal; IP, interparietal; ME, ossified portion of the mesethmoid; Mx, maxilla; Na, nasal; Pa, parietal; Per, periotic; Pl, palatine; PMx, premaxilla; pn, posterior nares; PS, presphenoid; Pt, pterygoid; s, symphysis of mandible; sh, stylohyal; SO, supra-occipital; Sq, squamosal; th, thyrohyal; Vo, vomer. (From Flower's Osteology.)
The vertebral column is remarkable for the fact that more or fewer of the cervical vertebrae may be fused together into a short and compact mass. This is seen at its maximum in the genera Balaena and Neobalaena. The odontoid process of the second vertebra, though hardly at all marked, is nevertheless really present and developed from a bony centre of its own, as in other mammals. The dorsal and lumbar vertebrae are, of course, to be distinguished by the presence of ribs attached to the former; but as there is only a rudimentary pelvis, not attached to the vertebral column, no sacral region can be detected. The caudal vertebrae are to be recognised by the -shaped chevron bones below.
Fig. 186.—Section through middle line of united cervical vertebrae of Greenland Right Whale (Balaena mysticetus). × 1⁄9. a, Articular surface for occipital condyle; e, epiphysis on posterior end of body of seventh cervical vertebra; sn, foramen in arch of atlas for first spinal nerve; 1, arch of atlas; 2, 3, 4, 5, 6, conjoined arches of the axis and four following vertebrae; 7, arch of seventh vertebra. (From Flower's Osteology.)
Fig. 187.—A, Sternum of Greenland Right Whale (Balaena mysticetus). × 1⁄15. B, Sternum of Common Rorqual or Fin Whale (Balaenoptera musculus). × 1⁄10. (From Flower's Osteology.)
The sternum in the Whale tribe is much more modified in the Whalebone Whales than in the Odontocetes. In the latter it is made up of several pieces, as in other mammals, which often, however, become coalesced. In the Mystacoceti this bone is a single piece, to which only one pair of ribs is attached, and its form is characteristic of the genus. It is heart-shaped, more or less, in Balaena, and somewhat cross- or -shaped in the genus Balaenoptera. In the Odontocetes the ribs have, some of them, the normal attachment by capitulum and tuberculum. In the Mystacocetes the attachment, where it exists, is very loose, and the tuberculum alone is attached to its vertebra. This allows of the freer play of the ribs during respiration. The scapula has a very characteristic form in these animals. The acromion, where it exists, is placed near the anterior margin of the shoulder blade, and overlaps the generally long coracoid process. Clavicles are totally absent. The pelvis is very rudimentary, consisting merely of a single bonelet, to which are attached the rudiments (in some cases) of a femur, and, in Balaena (Fig. 188), of a tibia also.
Fig. 188.—Side view of bones of posterior extremity of Greenland Right Whale (Balaena mysticetus). × ⅛. i, Ischium; f, femur; t, accessory ossicle representing the tibia. (After Eschricht and Reinhardt) (from Flower's Osteology.)
Whales are to be divided into three great groups:—(1) the Whalebone Whales or Mystacoceti; (2) the Toothed Whales or Odontoceti; and (3) the entirely-extinct Archaeoceti or Zeuglodonts.
Sub-Order 1. MYSTACOCETI.
This division is thus characterised:—Teeth are never functionally developed; they are present in the young, but replaced in the adult by the baleen or whalebone; the external respiratory aperture is double; the skull is perfectly symmetrical; the rami of the mandible are arched outwards and do not form a true symphysis; the sternum is always composed of a single piece of bone; the ribs articulate only with the transverse processes of the vertebrae.
The Mystacoceti are nearly invariably huge creatures, the sole exceptions being the Pygmy Right Whale, Neobalaena, and a small Rorqual. But even these are larger than the majority of Toothed Whales.
The most characteristic feature by which the Whalebone Whales are to be distinguished from other Whales is that which gives to them their name, the presence of whalebone. Whalebone is a horny product of the epithelium lining the mouth, and is comparable to an exaggeration of the transverse ridges which are found in the mouths of all mammals upon the palate. In non-Cetacean mammals these ridges vary in depth, and are arranged as a rule transversely, but with an oblique inclination. This is precisely how the plates of baleen are disposed in the mouth of a Whale. Each piece of "bone" is triangular in shape, the broader end being that of attachment while it narrows gradually; the inner side of the blades is frayed out into a number of threads which form the straining apparatus. The plates vary in length up to as great an extreme length as 13 feet, which occurs in the Right Whale at times. The colour is black or paler, even white. The number of these plates in the mouth is very great. As many as 370 blades have been counted. They diminish in length towards both ends of the series. Though whalebone has been in use for a long period, whence the whalebone came was formerly one of those things not generally known.
Fig. 189.—Section of upper jaw, with baleen plates, of Balaenoptera. a, Bone of jaw; b, gum; c, straight edge of baleen plate; d, e, frayed out surface of baleen plates. (After Owen.)
A very prevalent notion was that the whalebone formed the eyelids or perhaps the eyelashes of the creature. Scaliger, commenting upon Aristotle, held that the whale had "lamellae upon the eyebrows, which, when the head is plunged below the surface, were raised by the water; but when the animal raised its head above the waves the lamellae fell and covered the eyes." Whalebone, too, has been often spoken of as "the fin of a whale," "the finnes that stand forth of their mouths." The value of whalebone is still great, in spite of various substitutes which are now used in its place. In the year 1897, for example, the value of this article was £2000 per ton. As a single Whale may produce several tons of this material, it is not surprising to find that the results of a whaling voyage may be very profitable.
Fam. 1. Balaenopteridae.—This genus Balaenoptera includes the Rorquals, which are Whalebone Whales of large size, differing from the Right Whales in three important external characters: the head is comparatively small; there is a dorsal fin; the throat is marked by numerous longitudinal furrows. The bones of the cranium are not so arched as in the Right Whales, and as a consequence the plates of baleen are shorter. The hand is only four-fingered. The cervical vertebrae are for the most part all free. One of the earliest records of a Whale stranded in the Thames was probably of a species of this genus in the year 1658, and is thus described by John Evelyn:—"A large whale was taken betwixt my land butting on the Thames and Greenewich, which drew an infinite concourse to see it, by water, horse, coach, and on foot, from London and all parts.... It was killed with a harping yron, struck in the head, out of which spouted blood and water by two tunnells, and after an horrid grone it ran quite on shore and died. Its length was 58 foot, heighth 16; black skinn'd like coach leather, very small eyes, greate taile, onely two small finns, a picked snout, and a mouth so wide that divers men might have stood upright in it; no teeth, but suck'd slime onely as thro' a grate of that bone which we call whalebone, the throate yet so narrow as would not have admitted the least of fishes ... all of it prodigious, but in nothing more wonderful that an animal of so greate a bulk should be nourished onely by slime thro' those grates."
Professor Collett has recently given an elaborate account of the characters and habits of this great Whale (Balaenoptera musculus). Though a large beast (44 to 67 feet in length) it is exceeded by other Rorquals; it is of a dark grey blue colour above, white, for the most part, below. The dorsal fin is large and high; the flippers relatively slender and small. The whole throat from the symphysis of the jaws to the middle of the belly is, as in other species, marked by furrows, forty to fifty-eight in number. The hairy covering is reduced (in an adult female) to thirteen hairs on each side of the lower jaw; in a foetus there were also seven hairs on each side of the upper jaw, as well as rather more on the lower jaw—altogether, forty-eight. This Whale appears to feed chiefly upon small Crustacea, especially the Copepod, Calanus finmarchicus. The number of baleen plates is about 330 on each side of the jaw. This Whale sometimes swims singly, but usually in schools of even as many as fifty.
Rudolphi's Rorqual (B. borealis) seems to be a perfectly inoffensive beast; it is said to be able to stay under water for as long a time as twelve hours.
A smaller species than the last is B. rostrata—at the outside 33 feet in length. Here the hairy covering is reduced to "two small hairs on the integument covering the apex of the lower maxilla." The colour is greyish black above, the underside white. On the other hand, B. sibbaldii, the Blue Whale, is the giant of its race, reaching a length of 85 feet. Its colour is a dark bluish grey, with small whitish spots on the breast. The dorsal fin is small and low with straight margins.
B. musculus, the Finner, is intermediate in size—not more than 70 feet. It seems doubtful whether the "sulphur bottom," B. australis, of Antarctica and B. patachonica differ specifically from this.
The genus Megaptera is very near Balaenoptera, but differs from it mainly in the following external and internal characters. The dorsal fin is not very prominent, and its place is taken by a lowish hump, whence, indeed, the common name of this Whale, "Humpback." The pectoral fin is unusually long, and the creature uses it to beat itself, the surrounding water, and, more playfully, its mates. The general outline of this Cetacean is more clumsy than that of Balaenoptera. The most important internal difference is in the form of the scapula, which has at most a slight acromion and coracoid process. These are rather more pronounced, according to Messrs. van Beneden and Gervais, in the southern form of the genus, which is known as M. lalandii. The head, it should also be remarked, is studded with large tubercles about the size of an orange, which seem to be hyper-trophied rudiments of the hairs, which should be present in this region of the body. As is the case with other Whales, numerous species have been made out of individuals of Megaptera. Captain Scammon, who observed many "gams" or herds of these Whales, remarked that he had extreme difficulty in finding any two individuals precisely alike! The best-known species in any case is the northern M. longimana, which occurs on our own coasts. The genus is, like so many Cetaceans, world-wide in range; and it is possible that the difference in the scapula already referred to may justify the separation of a southern M. lalandii (with which in that case, perhaps, M. capensis and M. novae zelandiae will be synonymous). Quite recently M. Gervais has insisted upon a Megaptera indica from the Persian Gulf. Megaptera grows to a length of 50 to 60 feet. Seventy-five feet have been stated, but measurements of Whales have usually to be received with caution.
Rhachianectes, with but one species, R. glaucus, the "Californian Grey Whale," is the last genus of the family Balaenopteridae. This Whale is but imperfectly known anatomically; but quite sufficient has been ascertained to show its great divergence from Balaenoptera or Megaptera. The dorsal fin is completely absent, and the throat pleats, so characteristic of the typical Balaenopteridae, are reduced to two. It has, however, the general outline of a Rorqual, with a relatively small head. In osteological characters it tends to unite the two families Balaenopteridae and Balaenidae (if they are really necessary subdivisions). The skull is on the whole Rorqual-like; but its fore-part is narrow as in the Greenland Whale, and the premaxillaries are pinched up in the middle line so as to be visible from the side; this again is a Balaenid character. The cervical vertebrae are free as in Rorquals, and the sternum is quite as in that group. The scapula has more the shape of that of Balaena.
Rhachianectes glaucus is confined to the Pacific, and has been extensively hunted from the shore. It is not, however, a very valuable Whale, since the baleen is short as in Rorquals, and the beast, moreover, appears to be fierce, a somewhat rare attribute of Whales. It has been spoken of, indeed, as "a cunning, courageous, and vicious" animal. Rhachianectes is essentially a coast Whale, and loves to lie in the surf in quite shallow water waiting for the tide to float it off. This Whale varies much in colour from black to mottled grey and black, and reaches a length of about 40 feet.
Fam. 2. Balaenidae.—The Right Whales of the genus Balaena are to be distinguished from Neobalaena and from the Rorquals by the following characters:—
The size is large, 50 to 60 feet. There is no dorsal fin. The head is more than or nearly one-fourth of the entire length of the animal. The baleen is very long. The throat is not grooved. The orbital process of the frontal is not wider than the downward process of the maxilla. The cervical vertebrae are all fused. The scapula is rather high. The hind-limb has the rudiment of a tibia. The intestine has no caecum.
A vast number of different genera have been founded on detached bones, bits of whalebone, and more or less complete skeletons of Right Whales coming from different parts of the world. In Dr. Gray's catalogues we find the following allowed, viz. Balaena, Eubalaena, Hunterius, Caperea, Macleayius. The number of "species" distributed among the genera is some thirteen or more, with whose names we shall not trouble the reader. As a matter of fact there are not more than two species which can with certainty be identified and distinguished, both of which are so close that they cannot possibly be placed but in the same genus, Balaena. In no group of Whales—in no group of animals probably—has imagination run riot to so terrible an extent in the formation of genera and species as in these Right Whales. This multiplication or rather division of genera has arisen from an old idea that Whales coming from different seas must be of different kinds, a notion now thoroughly exploded.
The term "Right Whale" simply means that the Whales of this genus are the right kind of Whale for the whaler to pursue. Their whalebone is longer and more valuable, while the oil is not only more abundant but of a superior quality. The two species demand a separate account.
The Greenland Whale, Balaena mysticetus, is one of the rare instances of a Whale which has an exceedingly limited range in space. It is absolutely confined to the Arctic Ocean, and reported occurrences on our coasts are due to a confusion with B. australis, to be presently described. At the "Devil's Dyke," near Brighton, there is, or was, the skull of a most flagrant Rorqual, which is carefully labelled "Greenland Whale." This Whale grows to a length of 50, 60, rarely 70 feet. It is black in colour, save for a white patch on the under side of the jaw. The head is quite one-third of the body in length. There are a few scattered hairs at the extremity of the jaws. The length of time which this Whale can endure immersion has been variously stated. The utmost limit of endurance is stated by Scammon to be one hour and twenty minutes. The pursuit of this Whale is attended by dangers, not in the least because the animal is itself fierce and ready to attack, but simply on account of the velocity with which, and the great depth to which, it will dive, and also to the huge muscular force which is exerted in its struggles to free itself from the harpoons. It is indeed an extremely timid beast. It has been remarked that "a bird alighting upon its back sometimes sets it off in great agitation and terror." Combined with this timidity of disposition is an intense affection for its young, "which would do honour," observed Scoresby, "to the superior intelligence of human beings." Yet that trader and observer goes on to remark that "the value of the prize ... cannot be sacrificed to feelings of compassion"! The fact that this Whale and its congener, B. australis, feed among swarms of minute pelagic creatures, which they engulf in their huge mouths, led the ancients to believe and assert that they fed upon water only. When the Whale feeds it moves along with some velocity, taking in huge mouthfuls of sea water with the contained organisms, which are then strained off by the whalebone and left stranded upon the tongue.
Unlike its congener, the southern Right Whale, B. australis, is world-wide in distribution, avoiding only the Arctic regions. Where the Greenland Whale is found B. australis does not exist. The principal differences which it shows from B. mysticetus are firstly in the relatively shorter head and shorter and coarser whalebone. In the second place it has more ribs, fifteen pairs as against thirteen; but there is apparently some little confusion in the matter of ribs. An additional rib at the end of the series is apt to get lost, and in the skeleton of so huge and unmanageable a beast there is nothing more unwise than to insist upon, as specific characters, what may be due merely to defective preparation. This Whale has often, and the Greenland Whale also, a rough horny protuberance upon the snout known as the "bonnet." The causation of this is not clear. It has been spoken of as "a rudimentary frontal horn." But this suggestion of an Ungulate affinity can hardly be accepted. It seems to be more like a kind of corn.
This Whale was once more abundant on the coasts of Europe than it is to-day; it was much hunted by the Basques in past time. The Whale which frequented the Bay of Biscay was usually called the Biscayan Whale or B. biscayensis; but there is probably no specific difference. Among the small towns which fringe the Bay, it is very common to find the Whale incorporated into the armorial bearings. "Over the portal of the first old house in the steep street of Guetaria," writes Sir Clements Markham, "there is a shield of arms consisting of Whales amid waves of the sea. At Motrico the town arms consist of a Whale in the sea harpooned, and with a boat with men holding the line." Plenty of other such examples testify to the prevalence of the whaling industry on these adjoining coasts of Spain and France. It appears that though the fishery began much earlier—even in the ninth century—the first actual document relating to it dates from the year 1150. It is in the shape of privileges granted by Sancho the Wise to the city of San Sebastian. The trade was still very flourishing in the sixteenth century. Rondeletius the naturalist described Bayonne as the centre of the trade, and tells us that the flesh, especially of the tongue, was exposed for sale as food in the markets.
M. Fischer, who, as well as Sir Clements Markham, has given an important account of the whaling industry on the Basque shores, quotes an account of the methods pursued in the sixteenth century. It was at Biarritz—or as Ambroise Pare, from whom Fischer quotes, spelt it, Biaris—that the main fisheries were undertaken. The inhabitants set upon a hill a tower from which they could see "the Balaines which pass, and perceiving them coming partly by the loud noise they make, and partly by the water which they throw out by a conduit which they possess in the middle of the forehead." Several boats then set out in pursuit, some of which were reserved for men whose sole duty it was to pick out of the water their comrades who had overbalanced themselves in their excitement. The harpoons bore a mark by which their respective owners could recognise them, and the carcase of the animal was shared in accordance with the numbers and owners of the harpoons found sticking in the dead body of the Whale. At this period the fishery was at its height. But it continued to be an occupation along those shores until the beginning of the eighteenth century, after which it gradually declined. The fishery of Whales began to be carried farther afield than the shore, and for a long time the Basques furnished expert harpooners to whaling vessels proceeding to the Arctic seas. A curious example of the continuance of the fishery until at least 1712 is given by Sir C. Markham. In the parish records of Lequeito for that year, it is noted that a couple were married who possessed between them all the necessary outfit for a whaling cruise.
The genus Neobalaena is interesting from more than one point of view. Its size compared with its gigantic relatives is small, some 16 or 17 feet. The genus bears the same kind of proportion to Balaena that Kogia does to Physeter among the Physeteridae. It is one of those Whales which are very restricted in habitat; up to the present it is only known from the Antarctic region in the neighbourhood of New Zealand and South Australia. Structurally it is in a few points intermediate between the Right Whales and the Rorquals. The head is proportionately (as well as, of course, actually) not so large as in Balaena. There is a falcate dorsal fin; but the head in outline is not Rorqual-like in spite of its similar proportions. The whalebone is long. The throat is not grooved. Neobalaena has forty-three vertebrae, of which the cervicals are all fused. There are as many as seventeen or eighteen dorsal vertebrae, the largest number in any Cetacean as far as is known. With these are articulated not eighteen but only seventeen ribs. The first dorsal vertebra appears to be without a rib. The ribs are very broad and flat. The body thus gets an appearance of a Sirenian. The lumbar vertebrae are fewer than in any other Cetacean, being only two. The scapula is more like that of the Rorquals than that of the Right Whales; that is to say, it is long and not very high. The skull is most like that of Balaena, but the process of the frontal arching over the eye is broader relatively than in Balaena, and thus approaches Balaenoptera. Nothing is known of the viscera of this Whale. The whalebone is white, and the animal was first described by Dr. Gray from pieces of "bone." It is not always that so fortunate a diagnosis of specific or generic difference has been made from a structure which apparently offers so little aid for discrimination.
There is but a single species of the genus which is named Neobalaena marginata.
Sub-Order 2. ODONTOCETI.
The Odontoceti have teeth but no whalebone; the blow-hole is single; the skull is not symmetrical; some of the ribs are two-headed.
Fam. 1. Physeteridae.—This family of the Odontocetes may be thus defined:—All or most of the cervical vertebrae are fused together. The costal cartilages are not ossified. In the skull the pterygoids are thick and meet in the middle line; the symphysis of the mandible is long. Teeth, more or fewer, are found in both jaws, but those of the mandible are alone functional (? exc. Kogia). The pectoral limb is smallish. The throat is grooved by two or four furrows.
This family of Whales is again susceptible of division into the two sub-families—Physeterinae or Sperm Whales and the Ziphiinae or Beaked Whales. Professor P. J. van Beneden was strongly against any subdivision of what is here regarded as a perfectly natural family, embracing the Physeters and the Beaked Whales. There are, however, some reasons for the subdivision. The Ziphiinae have a reduced series of teeth, never exceeding two on each mandible, which contrasts with the fully-toothed mandibles of both Physeter and Kogia. The stomach of the Ziphioids is extraordinarily complicated even for a Cetacean. The small head of the latter group, which recalls in a curious way that of Mosasauroid reptiles and some Dinosaurs, is in contrast to the enormous head of the Cachalot and the very fairly-developed skull of the "Pygmy Sperm Whale." Both, however, furnish spermaceti, and in various osteological details come near together. On the whole we incline towards separating the Cachalots from the Ziphioids, and shall therefore commence with the former as being in some respects the more primitive members of the family Physeteridae.
Sub-Fam. 1. Physeterinae.—This sub-family may be thus defined:—Teeth in lower jaw numerous. No distinct lachrymal bone. Stomach with only four compartments (? as to Kogia).
Of this sub-family the best-known genus is Physeter, including the Sperm Whale or Cachalot. Of other reputed species we shall speak later. The genus is characterised in the first place by its large size—as much as 82 feet of length have been assigned to Physeter macrocephalus; but Sir William Flower thought that 55 or possibly 60 feet might be a better approximation to the greatest length of the Cachalot. The head is enormous, a third of the length of the body, and terminates in a massive and bluntish snout. This is, however, not so abruptly truncated as is often represented in figures. According to Messrs. Pouchet and Chaves, it slopes forward two metres beyond the end of the lower jaw; the mouth is thus ventral and almost shark-like in position, as is the case also with the Pygmy Sperm Whale, to be considered later. In connexion with this peculiar position of the mouth, it has been asserted—Mr. F. T. Bullen figures it—that the Sperm Whale turns over upon its back to bite. The blow-hole is single, and shaped like the sound-hole of a violin; it lies upon one side, and is not median in position. The throat is grooved as in the Ziphioids by two grooves. The dorsal fin is represented by a whole series of lowish humps, decreasing in elevation from before backwards. The pectoral fins are not large relatively speaking. The great square head is not occupied entirely by the skull; the cavity lying above, which is of course traversed by the tube ending in the blow-hole, is filled with the spermaceti, which is fluid fat during the life of the animal. Spermaceti also occurs in other Whales; and that of Hyperoodon, whence it has been extracted for commercial purposes, is said to offer no differences of importance from the spermaceti of the Sperm Whale. Spermaceti as a drug appears to have been first mentioned in the pharmacopoeias of the famous medical school of Salerno towards the year 1100. But it was confounded with a totally distinct substance, viz. ambergris. The confusion was also made by the famous alchemist Albertus Magnus, and by the observant Archbishop of Upsala, Olaus Magnus, in his work De gentibus septentrionalibus. It was supposed in fact by these writers to be the liberated sperm of the Whale, hence obviously the name. Later on, the substance in question was regarded as the brain of the Cachalot, in fact as late as the middle of the eighteenth century. It was Hunter and Camper who really discovered the true nature of the substance, oil of course, in the cavities of the skull. The huge skull of Physeter "is perhaps the most modified from the ordinary type" of skull in the whole mammalian class.
The top of the skull rises into a huge crest lying transversely, and from it slope forward two lateral crests formed from the maxillary bones; in this great basin lies the spermaceti already referred to. The skull, as in Toothed Whales generally, is exceedingly asymmetrical. The right premaxillary and the left nasal bones are much larger than their fellows; indeed the right nasal is hardly present as a separate bone. The parietal if present is fused with the supra-occipital. The jugal is large, and is not divided into two pieces as it is in the Ziphioids. The pterygoids meet below for a considerable distance, as in many Dolphins, and in the Edentata among other mammals. The symphysis of the lower jaw is very long, but the bones do not appear to be ankylosed. The length of the symphysis recalls that of the Gangetic Dolphin, Platanista.
In the vertebral column the atlas alone is free, the remaining cervicals being fused. There are only eleven dorsal vertebrae, eight lumbars, and twenty-four caudals. The breastbone of this Whale is a roughly-triangular bone made up of three pieces. Four cartilaginous sternal ribs are attached to this bone. The scapula is remarkable for the fact that it is concave on the outer and convex on the inner surface; otherwise it is quite typically Cetacean in form. The shortness of the pectoral limb is shown by the phalangeal formula, which is as follows:—I 1, II 5, III 5, IV 4, V 3.
One of the reasons for the pursuit of the Sperm Whale is the desire to obtain that extremely valuable product ambergris. This substance has long been known; but its true nature was for centuries in dispute. In Dr. Johnson's Dictionary (so recently as the edition of 1818!) ambergris is provided with alternative definitions; it is either the excrement of birds washed off rocks, or honeycombs that have fallen into the sea!
An old writer asserted of ambergris that it was "not the scum or excrement of the whale, but issues out of the root of a tree, which tree, howsoever it stands on the land, alwaies shoots forth its roots towards the sea, seaking the warmth of it, thereby to deliver the fattest gum that coms out of it, which tree otherwise by its copious fatness might be burnt and destroyed." These "explanations" were caused by the fact that ambergris is sometimes found floating in the sea. Ambergris is, of course, a product of the intestinal canal of the Sperm Whale; it seems to be of the nature of cholesterin, and its place of origin was conclusively proved by finding the beaks of cuttle-fish imbedded in it. When first extracted from the alimentary canal it is of greasy feel and consistency; later it hardens, and acquires its characteristic sweet earthy odour. Ambergris is used mainly as a vehicle for scents, and is a costly substance. A piece weighing 130 lbs. was valued at £500. Though now entirely used in connexion with perfumery, it was held by the ancients to be of great value as a specific in certain diseases.
The Sperm Whale is chiefly a tropical animal. Examples that have been cast up on our shores are strayed individuals. It often goes about in herds, which seem to be composed of females. Its food is chiefly cuttle-fishes, and it is said to have a predilection for those colossal cuttle-fishes whose existence has until recently been doubted. Mr. Bullen has sketched a conflict between these two giants of the deep. On the other hand it is said that its large throat, more than big enough to swallow a man (the Whale is credited with being that which swallowed Jonah), does not usually admit fishes larger than Bonitos and Albacores.
The ferocity of the Cachalot has been denied and affirmed. It certainly has great strength, for it can throw itself completely out of the water. Captain Scammon thinks that ships which are mysteriously lost at sea, with no obviously assignable cause, are sometimes the victims of the furious rushes of a bull Sperm Whale. Marco Polo took much the same view, but suggested that the Whale did not deliberately attack the ship, but was deceived by the foam following in its wake into thinking "there is something to eat afloat, and makes a rush forward, whereby it shall often stave in some part of the ship."
Sir W. Flower and many others are of opinion that there is but one species of Cachalot. But many names have been given to supposed other forms. The genus itself has even been divided, and to a set of vertebrae from the south Dr. Gray gave the perfectly superfluous name of Meganeuron kreffti. The "High-finned Cachalot" rests mainly upon the suggestions of Sir Robert Sibbald. It is supposed to have a high dorsal fin, and teeth in the upper as well as in the lower jaw. Common though it was asserted by its describer to be, there is not a bone, not a fragment even of a bone, alleged to belong to Physeter tursio in any museum in the world! It seems premature, therefore, to include this mysterious creature in any list of Cetacea, though that was done by no less a naturalist than the late Mr. Thomas Bell. It is this creature round which most of the stories of ferocity congregate. It is held to be the monster from which Perseus delivered Andromeda, and which was about to devour Angelica upon the shore of Brittany. The fact of the matter is, that the Sperm Whale, like so very many other Whales, is world-wide in range; and those naturalists who did not believe in so wide a distribution found themselves obliged, in order to satisfy their own views, to create new species for those of distant localities. Hence the dozen or so of synonyms which refer to what is to be called Physeter macrocephalus.
The genus Kogia (sometimes written Cogia), the so-called "Pygmy Sperm Whale," is a southern form of much smaller dimensions than its gigantic ally just described. Kogia does not exceed 15 feet or so in length. It differs from Physeter also in the well-marked and falcate dorsal fin, in its generally delphinoid form, in the short snout, and the more normal (for a Whale) shape of the blow-hole, which is crescentic.
There are also a number of osteological characters in which the two Physeterines differ from each other. In Kogia all the cervical vertebrae are ankylosed together; the skull is short, though equally asymmetrical; the ribs are as many as twelve or fourteen; the scapula has not the concave face that it has in Physeter. The functional teeth of the lower jaw seem to be reinforced by two on each side of the upper jaw. Moreover, the articulation of the ribs with the vertebrae does not show the very anomalous state of affairs that characterises Physeter, where the two heads of a rib may be upon one vertebra.
While there is no doubt as to the generic distinctness of Kogia, there is again the same difficulty that is met with throughout the whole of the order in settling into how many species the genus requires dividing.
We can dismiss, as unnecessary, additional generic names (Euphysetes, Callignathus), but there do appear to be reasons for allowing two species, if the accounts of their osteology are to be depended upon. One of these is K. breviceps, with thirteen pairs of ribs, no teeth in the upper jaw, fourteen or fifteen on each side of the lower jaw, vertebral formula C 7, D 13, L 9, Ca 25, and phalangeal formula I 2, II 8, III 8, IV 8, V 7.
The other will then be K. simus, with fourteen pairs of ribs, two teeth in the upper jaw, nine in each ramus of the lower jaw, vertebral formula C 7, D 14, L 5, Ca 24, and phalangeal formula I 2, II 5, III 4, IV 4, V 2.
A Californian species has been called K. floweri, whose teeth seem to be particularly long and recurved. And the New Zealand K. pottsi has been held to be also a distinct form. There seems to be nothing of special interest to record about the way of life of these Cetaceans, which are but imperfectly known.
Sub-Fam. 2. Ziphiinae.—Teeth in the lower jaw not more than two on each side. A distinct lachrymal bone. Stomach with very numerous compartments.
These Whales are all of moderate size, not exceeding 30 feet or so in length. They have a falcate dorsal fin rather near the end of the body; the muzzle is prolonged, hence the name often given to them of "Beaked Whales." The throat is grooved; the blow-hole is single and median, crescentic in form, with the concavity pointing forwards. A character possibly differentiating the Ziphioids from other Whales is the fact that the body ends in a rounded projection between the flukes of the tail. This has at any rate been noted in Mesoplodon, Ziphius, and Hyperoodon. The Ziphioid Whales are by no means common; indeed of Berardius but four or five specimens have ever been met with. Most of them are southern in range, and the vast stretches of desolate coast which occur in these regions of the world account possibly for the rarity of their remains. These Whales have done duty more than once for the "Sea Serpent." Quite recently an alleged sea serpent turned out to be a couple of Mesoplodon lying head to tail! The head in these Whales is small compared to the body. The skull is characterised by the strong maxillary crests, enormously developed in the male Hyperoodon. The vertex of the skull too is raised, forming a pronounced prominence behind the aperture of the nares (blow-hole); in many forms the rostrum is made of very dense bone, and is thus relatively abundant in rock strata. The pterygoids meet in the middle line as in the Cachalot. In addition to the few functional teeth in the lower jaw there are more numerous but small teeth in the upper jaw. These are not always to be recognised, as they are not attached to the bone, but merely imbedded in the gums, so that they come away when the skull is prepared.
The genus Berardius differs from Mesoplodon by its rather more symmetrical skull, of which the vertex is formed by the nasals. The mesethmoid is only partly ossified. The teeth are two on each side of the mandible, with their apices directed forwards. The vertebral formula is C 7, D 10, L 12, Ca 19.
B. arnouxi, from the seas of New Zealand, is the only species of this genus which is well known. It is 30 or 32 feet in length, and is of a velvety black colour, with a greyish belly. Instead of lowing like a cow, this Whale has been described as "bellowing like a bull"! A singular and somewhat inexplicable fact has been stated of this species. The teeth were said to be protrusible, and Sir James Hector stated that the teeth were imbedded "in a tough cartilaginous sac which adheres loosely in the socket of the jaw, and is moved by a series of muscular bundles that elevate or depress it." Sir William Flower justly observed that these statements "accord so little with anything hitherto known in mammalian anatomy that further observations on the subject are extremely desirable." Like other Ziphioids, Berardius feeds mainly, if not entirely, upon cuttle-fish, a prey eminently suited to their almost toothless mouths. It is not known whether Berardius has the Ziphioid grooves upon the throat. Nothing is known of the structure of the internal viscera of this Whale. It appears not to be really limited to the region of New Zealand, as is often stated, for Malm has lately described a skull (Berardius vegae) from Bering's Straits.
Mesoplodon is a world-wide genus embracing a number of species; on the lowest estimate seven species can be distinguished, and Sir W. Flower would add two more. These are moderate-sized Whales, 15 to 17 feet in length. In the skull the mesethmoid is ossified; the nasals are sunk between the upper ends of the premaxillae. There are but a single pair of teeth in the mandible attached to nearly the middle of its length (whence the generic name). The vertebral formula is C 7, D 9 or 10, L 10 or 11, Ca 19 or 20. The sternum consists of four or five pieces. The amount to which the cervical vertebrae are fused varies; but some are always fused.
The only species which has ever been stranded on the shores of this country is M. bidens, an example of which was described many years ago as the "Toothless Whale of Havre"; it was an old animal which had probably lost its teeth. Nevertheless it received the separate generic and specific name of Aodon dalei. The animal lived for two days out of the water, and made a sound like the "lowing of a cow." An instance of the rarity of the Whales of this genus is afforded by M. europaeus, of which only a single skull is known; this was extracted from a dead body, found floating, about the year 1840. It has never appeared since. M. layardi is remarkable on account of the very large size of its strap-shaped teeth; these curve over the upper jaw in such a way as to prevent the animal from fully opening its jaws. The case is curiously paralleled by the Sabre-toothed Tiger. This species is antarctic in range. From the opposite extremity of the globe comes M. stejnegeri, again known by but a single skull. It is singular on account of the large size of the brain case, and is a native of Bering's Straits. M. hectori has its two teeth situated quite at the extremity of the mandible, and in this feature approximates to the genus Berardius. It was, indeed, confounded with that genus by one naturalist.
Ziphius is a genus which is also of world-wide range. Here again the number of species is at present merely a matter of opinion. The prevalent impression, however, is that but a single species exists, which will therefore have the name of Z. cavirostris. The genus (and for the matter of that the species too) may be thus characterised in comparison with its allies. The mesethmoid is ossified as in Mesoplodon, but the nasals joined together form the vertex of the skull. There are two teeth near the symphysis of the mandible, besides the usual small and "functionless" teeth in the upper jaw. The vertebral formula is C 7, D 9 or 10, L 11, Ca 21.
The throat of a Ziphius from New Zealand was described by Messrs. Scott and Parker as having three grooves on each side. Whether this form is the same as von Haast's Z. novae zelandiae is a matter of doubt; but the individual to which his name has been applied was 26 feet long, and had but a single groove on each side. Even in the external characters of many Whales many points require clearing up. Our knowledge of Ziphius dates from the year 1804, when a skull "completely petrified in appearance" was picked up upon the Mediterranean coast of France, and described by the great Cuvier. It was forty years before another specimen was found. In the New Zealand specimen of von Haast already referred to, the body was scored by numerous lacerations. These wounds may have been due to fights among the Whales themselves; the forwardly-situated teeth would be capable of inflicting such wounds. But it has also been stated that the armed suckers of gigantic cuttle-fish are responsible for these scratches.
Hyperoodon is the most easily-distinguishable genus of Ziphioid Whales. Its characters are the following:—The skull has enormously-developed maxillary crests in the adult male; the mesethmoid is not fully ossified. There is but a single tooth to each ramus of the lower jaw, besides, of course, the usual small teeth in the upper jaw. The vertebral formula is C 7, D 9, L 9, Ca 18. The cervicals are fused into one mass, more or fewer being free in other Ziphioids. The sternum consists of three pieces only, the last of which is bifid posteriorly.
The name Hyperoodon was given to this Whale by Colonel Lacepède on account of the rough papillae upon the palate, which were mistaken by that observer for teeth. It is curious that the name is really appropriate in spite of this mistake, though of course it would be so to all the Ziphioids. In more than one feature this genus comes nearest of all the Ziphiinae to Physeter. Its enormous maxillary crests are paralleled in that Whale; but in Hyperoodon their great thickness contrasts with the thinness of those of the Cachalot. The correspondence in the attachment of a rib to its vertebra by both heads is noteworthy. It is remarkable that in this particular Hyperoodon is more like Physeter than the supposed nearest ally of the latter—Kogia.
Of this genus two species are known. The best known is the common northern H. rostratum (with many aliases); the second species from the southern hemisphere, H. planifrons, is only known from a single water- and pebble-worn skull. Its identification, however, depends upon the known accuracy of the late Sir William Flower.
The northern species (Hyperoodon rostratum) has often been recorded upon our own coasts; the first record of the stranding of this Whale was in the year 1717. In that year an example was found at Maldon, in Essex. Like the Beluga, Hyperoodon rostratum gets lighter in colour with advancing years. The young are black; the old animals pale brown with some white about them. The under surface, however, is always greyish white. The length of this Whale reaches to at any rate 30 feet. But John Hunter had a specimen which he believed to be 40 feet in length. The specimen, however, consisted only of a skull, so that error might have crept in. It has already been mentioned that the old males have enormous maxillary crests. According to M. Bouvier, who has lately made an exhaustive examination of the anatomy of this Whale, the females occasionally exhibit the same crests, which are thus presumably of the nature of spurs sometimes seen in old females among the Gallinaceous birds. The number of grooves upon the throat is in dispute in this Whale as in Ziphius. One pair is the usual allowance; but Kükenthal found four in some embryos studied by him. Attention has already been called to the voice of Ziphioid Whales. Hyperoodon neither "lows" nor "bellows," but "sobs"! Hyperoodon rostratum is a gregarious Whale, going about in herds, or "gams" as they should technically be termed, of four to ten or even fifteen. This Whale can leap right out of the water, and while in the air can turn its head from side to side, a capability which has not been mentioned in any other Whale. It can also stay under water for an unusually long period. Captain Gray, who has made an accurate study of this species, states that so long a period as two hours is the limit of endurance; this event occurred in the case of a harpooned Whale.
Fam. 2. Delphinidae.—This family, which includes the greater number of Cetacea, may thus be characterised:—Whales of small to moderate size. Teeth as a rule numerous, and present in the upper as well as in the lower jaw. Maxillae without large crests; the pterygoids, often meeting in the middle line, enclose an air space open behind. The anterior (five to eight) ribs are two headed, the posterior with tubercular head only. The sternal ribs are ossified.
The Dolphins and Porpoises, as already stated, embrace the greater number of existing species of Whales. Sir W. Flower and others who have followed him, allow nineteen genera. But as to the exact number of known species there is much uncertainty. That very careful observer, Mr. True, considers that there are fifty which demand recognition. As many as one hundred have received names. The matter is one which is perhaps barely ripe for decision. All the Dolphin tribe are, for Whales, smallish animals. The Killer Whale, Orca, is the only genus (or species?) which usually attains to more than moderate bulk. The rather mysterious Delphinus coronatus, 36 feet in length, of M. de Fréminville, would seem to be a Ziphioid; it was described as having a very pointed beak, and as having the dorsal fin situated near the tail; such characters suggest a Mesoplodon.
The genus Delphinapterus, the Beluga or White Whale, consists of but a single species, though as usual more than one name has been given to supposed different species. It is characterised as a genus by the following assemblage of structural features:—It has only eight to ten teeth occupying the anterior part of the jaws only. All the cervical vertebrae are free and unjoined. The vertebral formula is C 7, D 11 (or 12), L 9, Ca 23. The pterygoids are wide apart, though they converge as if about to meet at their posterior ends. There is no dorsal fin. The colour is white.
The Beluga is a northern species purely. The reputed form, D. kingii, was said to come from Australian seas; but there seems to have been an error in this statement. It is interesting to note that the white colour, so characteristic of the genus and species, is not found in the young, which are blackish. They gradually pale as they advance towards maturity. Delphinapterus leucas reaches a length of 10 feet, and like other Porpoises will ascend rivers in search of food. It is said to be specially addicted to salmon. Among the contents of the stomach have been found quantities of sand. But this habit of swallowing sand or pebbles has been noted in other Whales. Whether it is or is not accidental (taken in with ground-living food), it seems hardly likely that it is used for purposes of ballast! The Beluga has a voice; but the name "Sea Canary" is hardly suitable to it. A specimen of this species, recently described from the shores of Scotland (it is often thrown up upon our coasts), which had got entangled in the stakes of a new net, was regarded by the natives, on account of its white colour, as a ghost. Externally, besides its colour, the Beluga is remarkable for possessing a distinct neck, which is correlated of course with the freedom of the cervical vertebrae, and is also seen in Platanistidae.
The Narwhal (Monodon) is closely allied in structure to the last genus. It has the following anatomical characters:—The teeth are reduced to a single "horn" in the upper jaw, which is rudimentary in the female. The neck vertebrae are free. The vertebral formula is C 7, D 11, L 6, Ca 26. The pterygoids are as in Delphinapterus, and, as in that genus, there are no hairs upon the face or dorsal fin.
This genus is of course most obviously characterised by the twisted tusk of the male, which is occasionally double. This tusk has given to the only species of the genus, M. monoceros, both its generic and specific name. The animal has a spotted colour; but, as in the case of the Beluga, old animals tend to become white. The use of its horn to Monodon has been debated. In the first place it is clearly a secondary sexual character. The males have been observed to cross their horns like rapiers in a fencing match. It may be that they are used in more serious combats. An ingenious suggestion is that the long and strong tusk enables its possessor to break the thick ice and make a breathing hole. A third suggestion is due to Scoresby, who was led to make it from having taken out of the stomach of a Narwhal a large skate. He held that with its tusk the Whale empaled the fish and then swallowed it. The Narwhal is not large, 15 feet or so in length. But Lacepède, who was apt to compile with lack of discrimination, speaks of 60 feet long Narwhals. Monodon is purely Arctic, and but three or four specimens have ever been cast up on our shores.
Of true Porpoises, genus Phocaena, there are apparently several species. The genus itself has the following characters:—The teeth are sixteen to twenty-six on each half of each jaw; their crowns are compressed and lobed. The pterygoids do not meet. The dorsal fin has a row of tubercles along its margin.
The Porpoise of our coasts, P. communis, is a smallish species 6 to 8 feet in length. There are two to four hairs present in the young; its colour is black, generally lighter on the belly. The first six cervical vertebrae are fused. The ribs vary in number from twelve to fourteen pairs. It is a gregarious Whale, and will ascend rivers; it has been seen for example in the Seine at Paris. The name Porpoise is often written Porkpisce, which of course shows its origin. Very conveniently it was regarded as a fish, and therefore allowed to be eaten in Lent. The celebrated Dr. Caius, a gourmet as well as a physician and the refounder of a college, invented a particular sauce wherewith to dress this royal dish. Some time since Dr. Gray described a Porpoise from Margate as a distinct species (see p. 342) on account of the tubercles, which are now known to be a generic character.
Dr. Burmeister's P. spinipennis seems, however, to be really distinct. It was captured near the mouth of the Rio de la Plata. It is more tuberculated on the fin and back, and has fewer teeth (sixteen as against twenty-six).
Mr. True's P. dallii of the Pacific (where the Common Porpoise also occurs) is characterised chiefly by its very long vertebral column, consisting of ninety-eight vertebrae; there are only sixty-eight in the other species. The Eastern genus Neomeris is placed with Phocaena by Dr. Blanford. It practically only differs by the absence of a dorsal fin. It is only about 4 feet long, and inhabits the seas of India, Cape of Good Hope, and Japan. The one species is called N. phocaenoides.
The genus Globicephalus is to be defined thus:—Teeth seven to twelve on each side, confined to anterior end of jaws. Skull raised into a prominence behind the blow-hole; pterygoids large and in contact. Pectoral fin long and falcate; dorsal fin present. No beak. Vertebral formula C 7, D 11, L 11 to 14, Ca 27 to 29. Six pairs of the ribs are two-headed.
The best known species of the genus is the Ca'ing Whale, G. melas. This animal reaches a length of 20 feet, and is thus one of the largest of the Delphinidae. It is gregarious and was, even is now, much hunted in the Faeroe Islands. Its sheep-like habits (embodied in one scientific name deductor) enable it to be easily driven on shore in herds, which are then harpooned. The foetus of this Whale has a few hairs; the number of phalanges in the two middle digits is very great, as many as eleven to fourteen. G. scammoni, G. brachypterus, and G. indicus are other reputed species of the genus allowed by True and Blanford.
Grampus is a genus allied to the last. It has no teeth in the upper jaw, and but three to seven in the lower jaw, near the symphysis of the mandible. The pterygoids are in contact. There is no beak, and the pectoral fin is long. There are twelve pairs of ribs, of which six are two-headed. Apparently there is but one species, G. griseus, known as "Risso's Dolphin." It is a Mediterranean and Atlantic form, and is not common.
The genus Orca has as characters:—Teeth ten to thirteen, long and strong. Pterygoids not quite meeting. Vertebrae C 7, D 11 to 12, L 10, Ca 23. The first two or three fused. The dorsal fin is long and pointed.
Of this genus there may be more than one species; but the best known is the Killer Whale, O. gladiator (Fig. 180, p. 341), often spoken of as the "Grampus." It is marked with contrasting bands of white or yellow upon a black body-colour. The animal grows to a considerable length, as much as 30 feet. Orca is a powerful and rapacious Whale; and Eschricht has stated that from the stomach of one, thirteen Porpoises and fourteen Seals were extracted. They will also combine to attack larger Whales, and Scammon has related how he witnessed such an onslaught upon a Californian Grey Whale. "Belua truculenta dentibus," observed Olaus Magnus of this Cetacean. The high dorsal fin has been much exaggerated in old drawings; it has been even represented as strong and sharpened at the end, so as to be capable of ripping open the belly of a Whale. The fact that it sometimes lies over a little to one side is responsible for another anecdote: that an example of this Whale was seen to retire with a couple of Seals tucked away under the flippers, another grasped by the dorsal fin, and a fourth in the mouth! "When an Orca pursues a whale," wrote Dr. Frangius, "the latter makes a terrible bellowing like a bull when bitten by a dog." It is probable, according to F. Cuvier, that this Whale is the "Aries marinus" of the ancients, certain bands of white upon the head giving an impression of curved horns. It may also be the "horrible Sea-satyre" of Edmund Spencer.
Allied to Orca, but distinguishable from it by some rather minute peculiarities, is Pseudorca. It may be thus defined:—Teeth eight to ten, much like those of Orca. Dorsal fin rather small, falcate. Vertebral formula C 7, D 10, L 9, Ca 24. Six or all the cervicals united. The curious fact about this Whale, which embraces only a single species, P. crassidens, is that it was first known in the fossil condition from remains discovered in the fens of Lincolnshire. An important day for cetologists was that on which a whole herd entered the Baltic and furnished material for a better study of this Whale. It is not, any more than its near ally Orca, confined to northern seas; for several examples, at first relegated to a distinct species (P. meridionalis), have been obtained from the seas round Tasmania.
Orcella (which has been written Orcaella) has fourteen to nineteen small sharp teeth in each half of each jaw. The pterygoids are widely separate. The dorsal fin is small and falcate. The vertebral formula is C 7, D 14, L 14, Ca 26. Seven ribs are two-headed, and five of them reach the sternum.
This genus contains but a single species, O. brevirostris, which is both marine and fresh-water in habit; it occurs in the Indian seas, and in the Irrawaddy even as far up as 900 miles from the sea. Some regard the fresh-water individuals as a distinct form, O. fluminalis.
Sagmatias is a genus known only from a skull, which is remarkable for the elevation of the premaxillae into a crest; the pterygoids are short, and there are thirty-two teeth in each half of each jaw.
Feresia is known from two skulls which are provided with ten to twelve teeth in each half of each jaw. It is intermediate between Globicephalus, Grampus, and Lagenorhynchus, according to Sir W. Flower.
The genus Delphinus contains the Dolphin, D. delphis. The genus may be characterised as follows:—Teeth small and numerous, forty-seven to sixty-five. Vertebral formula C 7, D 14 or 15, L 21 or 22, Ca 30 to 32. The atlas and axis are fused, the rest free. The palatal border of the maxillae is deeply grooved. The fins are falcate; the beak long and distinct.
The Common Dolphin of the Mediterranean shows so many variations of colour, slight differences in the proportions of the bones of the skull, and in the number of the teeth, that it has been divided up into at least seventeen "species." But M. Fischer, who has studied many of these forms, does not admit them, and most students of this group of mammals follow him in the matter. The Dolphin is and has been the most familiar of Cetaceans; in consequence it has accumulated much anecdote of a mythical character. The extreme intelligence and goodwill towards man assigned to this creature by the ancients are possibly due to the anomaly of a creature ostensibly a fish showing many of the characters of higher animals. Its unfishlike intelligence baffled the early observers, who at once endowed it with especially advanced attributes. Hence the stories of Arion and others. The leaping of the Dolphin out of the water is exemplified in many Mediterranean coins and coats of arms; the heraldic dolphin is represented with an arched back as in leaping. The Dolphin reaches a length of some 7 feet, and appears to be world-wide in range. Possibly distinct is D. longirostris, characterised, as the name denotes, by the very long beak; it has also more teeth and is a native of Malabar. D. roseiventris again may be a third species of Delphinus. It comes from Torres Straits, and has the under parts rosy in colour.
The genus Prodelphinus has, like Delphinus, a distinct beak; but it has not the grooved maxillaries. No other character of importance appears to separate it from Delphinus.
The genus consists of some eight widely distributed species, which are none of them large Dolphins.
Lagenorhynchus has the following assemblage of characters:—Head with short, not very distinct beak. Dorsal and pectoral fins falcate. Teeth small, twenty-two to forty-five in each half jaw. Vertebrae ranging in number from seventy-three to ninety-two. Pterygoid bones either in contact or separate. There are fifteen or sixteen pairs of ribs, of which six are two-headed. Of this genus Mr. True allows eight species, which have been increased by a ninth since the publication of his "Revision."
Two species of Lagenorhynchus are known from our coasts; the rest are mainly southern in range. The British species are, firstly, L. albirostris, a Dolphin of some 9 feet in length. It has a large number of vertebrae, ninety-two in number. L. albirostris is a rare species, the first record of its occurrence on these shores being in 1834. Since that date some eighteen individuals have been shot or stranded on the shores of the British Isles. The second British species, L. acutus, differs in colour from the first. As in the last, the upper parts are black and the under parts white; but in L. acutus there is also a stripe on the flanks, brownish in colour. It has fewer vertebrae, not more than eighty-two.
The next genus of Dolphins, Sotalia, is characterised by—Teeth tolerably large, twenty-six to thirty-five. The vertebral formula is C 7, D 11 or 12, L 10 to 14, Ca 22. The pterygoids are not in contact in the middle line. It has a distinct beak.
Of this genus there are some six species (the exact number, as in so many other genera, cannot be positively asserted), most of which are fluviatile or estuarine in habit. They are also on the whole characterised by their pale, if not actually white, coloration. S. sinensis of the Amoy is white with pinkish fins. Sotalia guianensis is American as its name denotes. It is figured by van Beneden as of a pale brown colour. It is very abundant in the Bay of Rio de Janeiro, and has the reputation of being a friend of man like some other Dolphins. The natives hold that it will bring to shore the bodies of drowned persons. The most singular species of the genus is that recently described by Professor Kükenthal as S. teüszii. This animal is purely fresh-water, being found in the Camaroon river, where it is extremely rare. The nostrils (blow-hole) are prolonged into a snout-like process, a fact which is of interest in connexion with the assertion that in Balaenoptera the blow-hole is puffed out during spouting. What is temporary in the Rorqual appears to be permanent in the Sotalia. More remarkable still, perhaps, is the assertion that it is a vegetable-feeding Dolphin. This is not a mere assertion except that it may not apply universally; for in the stomach of a specimen nothing but vegetable débris was found. But in the stomachs of other Whales (e.g. Rhachianectes) vegetable matter has also been found, which may perhaps have been taken in accidentally with the food.
Steno comes near Sotalia, and Dr. Blanford has transferred to it (under the one name of Steno perniger) the two species, Sotalia gadamu and Sotalia lentiginosa. It is, however, to be distinguished from Sotalia by the following characters:—Teeth large and few, twenty to twenty-seven on each side of each jaw, with furrowed surfaces to crowns. Vertebrae C 7, D 12 or 13, L 15, Ca 30 to 32. Pterygoids in contact. There are but two species apparently (not counting Dr. Blanford's).
Tursiops is not a very easily definable genus. These are its chief features:—Teeth large, twenty-two to twenty-six in number in each half of each jaw. Vertebral formula C 7, D 12 or 13, L 16 or 17, Ca 27. Pterygoids in contact. Beak distinct. Some five species are allowed; but it seems to be difficult to differentiate the others from Tursiops tursio. This, the best-known form, is quite or nearly world-wide in range, and occurs, though not abundantly, on our own coasts. Mr. True has observed that the eyelids of this Whale, which is largely hunted on the American coast, are as mobile as those of a terrestrial mammal. The name "tursio" is derived from Pliny. Belon would also derive from this word the French vernacular "marsouin." The latter term is sometimes regarded as a corruption of "Meerschwein," but it would seem to be more probably derivable from "marinum suem," from the Latin direct. T. tursio has the back black to lead-colour; the under parts white. In the reputed species, T. abusalam, from the Red Sea, the back is a dark sea-green. T. tursio reaches a length of 12 feet, but is more usually smaller.
The genus Tursio must be carefully distinguished from Tursiops. It has no dorsal fin, the teeth are small and numerous (forty-four), and the pterygoids are separate. There are two species, T. borealis and T. peronii, the former being northern and the latter more widely spread.
The genus Cephalorhynchus has for its chief characters the following:—Teeth twenty-five to thirty-one, small and sharp. Pterygoids widely separated. Dorsal fin not falcate, but triangular or ovate in form. Beak not well marked off from the head. The species of this genus are all southern in range; four are perhaps to be allowed.
Fam. 3. Platanistidae.—This family of Odontocetes may be distinguished from the Dolphins by the following assemblage of structural features:—Cervical vertebrae all free, and each one of some length (for a Cetacean). Jaws long and narrow, with a considerable length of symphysis. Teeth very numerous.
This very meagre series of differential characters is largely due to Pontoporia on the Platanistid side, and to Monodon and Delphinapterus upon the Delphinid side. Otherwise the family Platanistidae would be extremely distinct. The two last-named genera have separate cervical vertebrae, and in the Beluga at any rate this is expressed externally by a quite distinct neck. Moreover, as Mr. True has pointed out, the pterygoid bones have not the involuted cavity below which characterises other Dolphins; and they have, what other Dolphins have not, an articulation outwards with the roofing bones of the skull. Sir W. Flower described the fact that in Inia (and the same occurs in Pontoporia) the palatines are separated from each other by the intervention of the vomer. In this feature they resemble certain Ziphioids, Berardius, Oulodon (= Mesoplodon) grayi, and Hyperoodon. The true Dolphins also appear to show the same intervention of the vomer in a few cases. There is nothing, therefore, distinctive from the Delphinidae in this feature.
The existence of cartilaginous sternal ribs in Inia and Platanista shows affinity between these two genera and the Physeteridae. Pontoporia is Dolphin-like in this particular, as it is also in the mode of articulation of the ribs with the vertebral column. But this last matter has already been dealt with. The principal reason for placing Pontoporia with the other two genera is the close resemblance which its skull bears to that of Inia.
The first genus of this family which will be noticed is Platanista. The following are its main characters:—Dorsal fin absent. Eyes rudimentary. Pectoral fins large and truncated at the extremity. Teeth, about twenty-nine in each half of each jaw. Scapula with the acromion coinciding with its anterior edge. Skull with enormous maxillary crests, and with the palatines entirely concealed by the pterygoids. The length of the above definition will serve to indicate how anomalous in many particulars is the structure of this "Dolphin."
There is apparently but one species, P. gangetica, the "Susu." The Indian vernacular name is derived from the sound that the animal makes when spouting. It is an inhabitant of the Ganges and the Indus, together with their tributaries, and ascends very high up its streams. It is also thought to be purely fluviatile and never to desert the rivers for the sea. Platanista lives chiefly by grubbing in the mud for prawns and fish. Grains of rice have also been found in the stomach, but this would seem to be accidental. The long snout of the Susu has been compared to the long snout of the Gharial, a native of the same region. This Whale grows to a length of over 9 feet, but this length is exceptional. Its anatomy has been elaborately described by Dr. Anderson.
The next genus, Inia, is thus to be characterised:—Dorsal fin rudimentary; pectorals large and ovate. Teeth, as many as thirty-two on each side, often with an additional tubercle. Skull without large maxillary crests; palatines not hidden by pterygoids, but divided by vomer. The vertebrae of this genus are few in number, only forty-one in all, which are thus distributed: C 7, D 13, L 3, Ca 18. The peculiarities of the vertebral column are several. In the first place, as has been mentioned in the definition of the family, all the cervicals are separate and individually of some length. Secondly, the axis has a better trace of an odontoid process than in any other Whale except Platanista, where it is even more obvious. The lumbar region is remarkable on account of its restriction to three vertebrae. The sternum, by what we must regard as convergence, is somewhat like that of the Whalebone whales. It consists of one piece only, of a roughly-oval form, to which apparently only two pairs of (cartilaginous) sternal ribs are attached. In the fore-limb the proportions between the humerus and the radius are more like those of terrestrial mammals; i.e. the humerus is distinctly the longer, the converse usually obtaining among Whales. But Platanista again agrees with Inia. The teeth are remarkable for the fact that the hindermost ones of the series have an additional lobe; they are not purely conical as are those of Whales generally.
There is but one species, Inia geoffrensis, which inhabits the Amazons, and grows to a length of 8 feet. Its colour variations are rather extraordinary, unless they can be set down to sex, which has been denied. Some individuals are wholly pink; others are black above and pink beneath. This Whale is believed by the Indians to attack a man in the water, and it is added that the Sotalia of the same streams will defend him from these attacks! Naturally, therefore, superstitious reverence attaches to this Dolphin, which is tiresome to the naturalist who wants specimens, as Professor Louis Agassiz found.
In the genus Pontoporia the dorsal fin is well developed and falcate. The teeth are very numerous, 200 in all. The ribs articulate as in Dolphins. The skull closely resembles that of Inia, and the scapula is, as in that genus, "normal."
The proper name for Pontoporia is really Stenodelphis, which name was first used by Gervais a month or two before Gray, who separated it from the vague Delphinus of its original discoverer, Gervais himself. It has a longer snout than Inia, which, being bent towards the extremity in a downward direction, curiously suggests the skull of a Curlew. In details, however, the skull is exceedingly like that of Inia. It is nearly symmetrical. The vertebral formula appears to be the following:—C 7, D 10, L 5, Ca 20 = 42, just one over the number of the vertebrae in Inia. The sternum is in two pieces. Of the ten pairs of ribs the first three are double-headed. These and the next have sternal moieties joining the sternum, of which the first three are ossified, the last being apparently merely a ligament.
There is a single species of the genus, P. blainvillii. This Whale is described by Mr. Lydekker as being of a clear brown colour, harmonising with the waters of the estuary of the Amazons and the La Plata which it inhabits. The same colour characterises Sotalia pallida of those parts of the world, and may be a colour adaptation. But the extant accounts of the colour of this Dolphin vary—quite possibly in accordance with real variations, such as are exhibited by Inia already spoken of. Pontoporia blainvillii is a smallish Dolphin some 4 feet in length.
Fossil Odontocetes.—Several of the existing genera of Dolphins are also known in a fossil condition, as well as Ziphioid Whales closely related to existing forms. We shall deal here only with a few genera of fossil Odontocetes which depart in their structure from existing forms.
The genus Physodon is Miocene, and has been found in Patagonia. It appears to be most nearly allied to the Physeteridae, but should probably form a distinct family. Physodon was not so large as Physeter, the skull measuring only some 10 feet. It thus comes nearer in point of size to Kogia, and it is interesting to note that its relatively-shorter snout is also suggestive of the dwarf Cachalot. The general outline of the skull is, however, more like that of Physeter, and there is the same deep cavity for the lodgment of spermaceti. The main feature of interest in the skull is the presence of teeth in both jaws, and the fact that two or three are lodged in the premaxillae. This is precisely what is found in the most ancient Whales, the Zeuglodonts.
Extinct Dolphins, apparently referable to the Platanistidae, are the most numerous among the earlier forms of Cetaceans, and it is significant that the earliest known forms of these go back to the Eocene.
The genus Iniopsis of Mr. Lydekker, with one species, I. caucasica, comes from rocks which seem to be of that age. The back part of the skull of this animal, the only part of the skull known, has the same squarish excavation of the maxillaries that characterises Inia and Pontoporia. Its lower jaw was slender and possessed numerous teeth.
The long snout and jaws of Platanistids, especially exaggerated in Pontoporia among living forms, are constantly found in these Tertiary Platanistids.
Eurhinodelphis had a beak three and a half times the length of the cranium, whereas in Pontoporia the proportions are as 2:1. The teeth too were very numerous.
The genus Argyrocetus, from Patagonian Tertiary strata, was an animal about as large as the existing Dolphin. It had the slender rostrum and numerous teeth of the Platanistids and the squared excavations of the maxillaries. Argyrocetus patagonicus possessed also archaic characters, suggesting earlier affinities still. The two condyles of the skull instead of being closely adpressed to the skull stood out in a way more like that met with in terrestrial mammals. The nasal bones instead of being abbreviated rudiments are well developed as in the archaic Zeuglodonts. The cervical vertebrae of this Whale are all perfectly free from each other and individually long. The skull is on the whole bilaterally symmetrical; this again is a feature more pronounced among the Platanistidae than among other Odontocetes. Accompanying these generalised Cetacean characters are some which show that the animal was too specialised to be the direct ancestor of any existing forms. The end of the mandible was upturned and without teeth, its form being quite unique among Cetacea. Other allied forms, such as Zarrhachis and Priscodelphinus, showed the same length of the cervical vertebrae.
A very distinct family of extinct Whales is that of the Squalodontidae. They to some extent bridge over the gap between the existing Odontoceti and the Eocene Archaeoceti (Zeuglodonts).
The skull of these Whales was on the whole Dolphin-like. But they possessed teeth which were distinctly specialised into incisors, canines, and molars. The molars have a coarsely-serrated cutting edge as in the Zeuglodonts, and are also to some extent two-rooted. But they are more numerous, and so far approximate to the conditions which characterise the more typical modern Odontocetes. Squalodon was a long-beaked form, and Prosqualodon had a skull whose proportions are nearer those of Kogia.
Sub-Order 3. ARCHAEOCETI.
This division of the Whale tribe embraces but a single family, Zeuglodontidae, of which but a single genus, Zeuglodon, can with certainty be discriminated.
Zeuglodon is an Eocene form of large size, with teeth which are limited in number and disposed in three series as incisors, canines, and molars. The molars are double-rooted, a fact which has given to the genus its name. The nasal bones being long instead of rudimentary like those of other Whales, the blow-hole lies more in the middle of the face. The skull, too, is not Whale-like in a number of other points. Thus the premaxillaries take their fair share in the outline of the upper jaw; and, furthermore, bear the incisor teeth. The parietals meet above in a crest and are not excluded from the roof of the skull. The vertebrae of the neck are in no way shortened; neither are they fused together. The ribs are double-headed, and the sternum is made up of several pieces. Some naturalists, particularly Professor D'Arcy Thompson, have assigned a relationship to the Seals to these ancient Cetacea; but others have disputed this view chiefly on the grounds that the characters which appear to be Seal-like are simply characters which are generalised and so far at most not Whale-like. Thus the long neck and the serrated character of the teeth may be accepted as Seal-like on the one hand; but on the other, a simple serrated tooth and a long neck are not by any means features of organisation which we should consider out of the way in an ancient form of Cetacean which probably preyed upon fish. The humerus of Zeuglodon, according to Mr. Lydekker, puts out of court any possible near relationship to the Seals. But the matter under dispute can be further studied by reference to the three memoirs quoted below.
- See van Beneden and Gervais, Ostéographie des Cétacés; and for a more general account Beddard, A Book of Whales, London, Murray, 1900.
- Vergleichend-anatomische Untersuchungen an Walthiere, Jena, 1889-93.
- "And at his gills draws in, and at his trunk spouts out, a sea," wrote Milton, and think many others.
- These have been recorded by Professor Howes in the Porpoise.
- For details and literature see Jungklaus; Jen. Zeitschr. xxxii. 1898, p. 1.
- In Proc. Zool. Soc. 1886, p. 243.
- Perrin, "Notes on the Anatomy of B. rostrata," Proc. Zool. Soc. 1870, p. 805.
- von Haast, "Notes on a Skeleton of Balaenoptera australis," Proc. Zool. Soc. 1883, p. 592.
- Ostéographie des Cétacés, Paris, 1880, p. 130.
- Marine Mammals of the North-West Coast of North America, 1874.
- Cf. Scammon, loc. cit.
- The name that has priority seems to be glacialis.
- Proc. Zool. Soc. 1881, p. 969.
- Actes Linn. Soc. Bordeaux, 1881.
- For osteology see Hector, Trans. New Zeal. Inst. vii. 1876, p. 251; and Beddard, Trans. Zool. Soc. xv. 1901, p. 87.
- Journ. de l'Anat. xxvi. 1890, p. 270.
- The Cruise of the Cachalot, London, 1900.
- See Pouchet, "Contribution a l'histoire du spermaceti," Bergens Museums Aarbog for 1893, No. I.
- Yule, Travels of Marco Polo, ii. London, 1874, p. 231.
- See Flower, Trans. Zool. Soc. viii. 1872, p. 203.
- Bihang Svensk. Akad. Handl. viii. 1883.
- Flower, Trans. Zool. Soc. x. 1878, p. 415; and H. O. Forbes, Proc. Zool. Soc. 1893, p. 216.
- Trans. Zool. Soc. xii. 1889, p. 241.
- Ann. Sci. Nat. (7), xiii. 1892, p. 259.
- Proc. Zool. Soc. 1882, pp. 722, 726.
- Bull. U.S. Nat. Mus. No. 36, 1889, p. 7.
- See an essay on the hunting of this Whale, by S. H. C. Müller, in Fish and Fisheries, Edinburgh (Blackwood), 1883.
- Grampus being a contraction of grand poisson is an obvious name to apply to any Whale.
- See Actes Soc. Linn. Bordeaux, 1881; and for another figure, also coloured, Flower, in Trans. Zool. Soc. xi. 1880, pl. i.
- Bull. U.S. Nat. Mus. No. 36, 1889.
- Zool. Jahrb. Syst. Theil, vi. 1892, p. 442.
- Anatomical Researches Yunnan Exp. 1878, p. 417.
- Flower, Trans. Zool. Soc. vi. 1867, p. 106; and Burmeister, Proc. Zool. Soc. 1867, p. 484.
- Proc. Zool. Soc. 1892, p. 558.
- Thompson, Studies Mus. Dundee, i. 1890; and C. R. Congrès de Zoologie, 1889, p. 225.
- Lydekker, Proc. Zool. Soc. 1892, p. 560.