Chapter XII: Cetacea--Whales and Dolphins (1)

ORDER VI. CETACEA.[229]

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 {340} 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 {341} 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._ x 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 {342} 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, {343} 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 Mueller, 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. {344}

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 Kuekenthal's[230] 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 {345} 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 Kuekenthal 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_). x 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.[231] 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 {346} 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.[232]

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 {347} 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 Kuekenthal 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[233] 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, {348} 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 {349} 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; _rb_^1, first rib; _rb^{12}_, twelfth rib; _sc_, scapula; _s.occ_, supra-occipital; _st_, sternum; _uln_, ulna; _zyg_, prezygapophysis. (From Parker and Haswell's _Zoology_.)

FIG. 184.--Under surface of the cranium of a young Caa'ing Whale (_Globicephalus melas_). x 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_.)

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 {350} 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 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 {351} 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_). x 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 {352} 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 [234]-shaped chevron bones below.

FIG. 186.--Section through middle line of united cervical vertebrae of Greenland Right Whale (_Balaena mysticetus_). x 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_). x 1/15. B, Sternum of Common Rorqual or Fin Whale (_Balaenoptera musculus_). x 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 {353} form is characteristic of the genus. It is heart-shaped, more or less, in _Balaena_, and somewhat cross- or [235]-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_). x 1/8. _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 {354} 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 {355} 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 L2000 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[236] 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 {356} 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[237] 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.[238]

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,[239] {357} 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[240] 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_,[241] 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 {358} 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 {359} 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_,[242] 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 {360} 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,[243] "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,[244] 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 {361} 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; {362} 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_.[245]

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 {363} 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,[246] 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[247]--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 {364} 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.[248] 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_.