John Hunter states that the tongue, which is the organ of taste, is also endowed with the sense of touch. Ho found the tongue in the Porpesse and Grampus firm in texture, composed of muscle and fat, pointed and serrated on its edges like that of a hog. In the Spermaceti Whale, he says, it was almost like a feather-bed. In the Piked Whale it was but gently raised, hardly having any lateral edges, and its tip projecting but little, yet like every other tongue, composed or muscle and fat. He supposes that the tongue of the large Whale bone Whale rises in the mouth considerably ; the two jaws in the middle being kept at such a distance on account of the whalebone, so that the space between, when the mouth is shut, must be filled with the tongue.
Sight—The eye in the Herbivorous Cetaceans only is provided with a nictitating membrane, or lateral lid ; that of the Zoophagous or Spouting Cetaceans has no lachrymal glands, but the lids are furnished with glands for a mucous secretion adapted for lubricating the sclerotic coat.
John Hunter states that the eye in this tribe is constructed upon nearly the same principle as that of the quadrupeds, differing how ever in some circumstances, by which it is probably better adapted to see in the medium through which the light is to pass. It is upon the whole small for the size of the animal. The lids have but little motion, and consist not of loose cellular membrane, as in common quadrupeds, but rather of the common adipose membrane of the body; the connection however of their circumference with the common integuments is loose, the cellular membrane being less loaded with oil, which allows of a slight fold being made upon the surrounding parts in opening the eyelids. This is not to an equal degree, he adds, in them all, being less so in the Porpesse than in the l'iked Whale. A detailed account of the anatomy of the eye in whales will be found in Hunter's paper.
Hearing.—There is no external concha, but the ear is constructed much upon the same principle as in the quadruped • there are how ever certain differences which the reader will find set forth in Hunter's paper. The sense seems to be fairly developed, and whale-fishers experience no small difficulty from the warning given by both eye and ear. It has however been stated that the Greenland Whale, though not without a nice sense of hearing, remains insensible to the report of a cannon.
Touch.—The sensation of touch must be lively, though it is a commonly received opinion that the common Dolphin, notwithstanding its delicate epidermis, is not very sensible to tactile impressions. Messrs. Breschet and Roussel de Vanzeine distinguish the following constituents in the akin of the Cetaceans :-1. Derm, or corium, a dense fibrous cellular texture, which contains and protects all the other parts of the skin. 2. The papillary bodies, consisting of palate covered by the derm. 3. The sudorific apparatus, consisting of soft, elastic, spiral canals, which extend through the entire thick ness of the derm, and open in the intervals of the papilla; by an orifice, closed generally by a small epidermic valve. 4. The inhalent apparatus, 5. The mucous apparatus. 6. The colinifie apparatus.
According to Hunter, the reticular network containing the blubber, which is described by him as fine in the Porpesse, Spermaceti, and large halebone Whale (flahrita), and coarse in the Grampus end small Whalebone Whale (Baliraopt era), forms part of the skin.
In giving some illustrations of this large family we shall follow the arrangement of Dr. J. E. Cray as indicated above.
The following is a synopsis of the character of the genera of the first family Bahreithr a. Dorsal fin none. Belly smooth. Baleen elongate, slender. L Babson.
L. Dorsal tin distinct. Belly plaited. Baleen broad, short.
..11(9aptera. Pectoral fins elongate. Dorsal fin low.
3. flahrnoptern. Pectoral fins moderate. Dorsal fin falcate, length from nose. Vertebrie 54 or 64.
It is in the genus Bahraa that the baleen, or whalebone, is most highly developed. John Hunter describes this extremely elastic animal substance as being of the same nature as horn, a term which he uses to express what constitutes hair, nails, claws, feathers, &c. It consists, he remarks, of thin plates of some breadth and in some of very considerable length, their breadth and length in some degree corresponding to one another ; when longest they are commonly the broadest, but not always so. The plates differ in size in different parts of the same mouth, more especially in the large Whalebone Whale. "They are placed," continues Hunter, "in several rows, encompassing the outer skirts of the upper jaw, similar to teeth in other animals. They stand parallel to each other, having one edge towards the circumference of the mouth, the other towards the centre or cavity. They are placed near together in the Piked Whale, not being a quarter of an inch asunder, where at the greatest distance, yet differing in this respect in different parts of the same mouth ; but in the Great Whale the distances are more considerable. The outer row is composed of the longest plates ; and these are in proportion to the different distances between the two jaws, some being 14 or 15 feet long and 12 or 15 inches broad ; but towards the anterior and posterior parts of the mouth they are very short, they rise for half a foot or more, nearly of equal breadths, and afterwards shelve off from their inner side until they come near to a point at the outer : the exterior of the inner rows are the longest, corresponding to the termination of the declivity of the outer, and become shorter and shorter till they hardly rise above the gum. The inner rows are closer than the outer, and rise almost perpendicularly from the gum, being longitudinally straight, and have leas of the declivity than the outer. The plates of the outer row laterally are not quite flat, but make a serpentine line ; more especially in the l'ikocl Whale the outer edge is thicker than the inner. All round the line made by their outer edges runs small white bead, which is formed along with the whalebone, and wears down with it. The smaller plates are nearly of an equal thick ness upon both edges. In all of them the termination is in a kind of
hair, as if the plate was split into innumerable small parts, the exterior being the longest and strongest. The two sides of the mouth com posed of these rows meet nearly in a point at the tip of the jaw, and spread or recede laterally from each other as they pass back ; and at their posterior ends in the Piked Whale they make a sweep inwards, and come very near each other, just before the opening of the (eso phagus In the Piked Whale there were above 300 in the outer rows on each side of the mouth. Each layer terminates in an oblique surface, which obliquity inclines to the roof of the mouth, answering to the gradual diminution of their length ; so that the whole surface, composed of these terminations, forms one plane, rising gradually from the roof of the mouth : from this obliquity of the edge of the outer row we may in some measure judge of the extent of the whole base, but not exactly, as it makes a hollow curve, which increases the brew. The whole surface resembles the skin of an animal covered with strong hair, under which surface the tongue must immediately lie when the mouth is shut ; it is of a light•brown colour in the Piked Whale, and is darker in the Large Whale. In the Piked Whale, when the mouth is shut, the projecting whalebone remains entirely on the inside of the lower jaw, the two jaws meeting everywhere along theft surface ; but how this is effected in the Large Whale I do not certainly know, the horizontal plane made by the lower jaw being straight, as in the Piked Whale; but the upper jaw being an arch cannot be hid by the lower. I suppose therefore that a broad upper lip, meeting as low as the lower jaw, covers the whole of the outer edges of the exterior rows. The whalebone is continually wearing down, and renew ing in the same proportion, except that when the animal is growing it is renewed faster and in proportion to the growth. The formation of the whalebone is extremely curious, being in one respect similar to that of hair, horns, spurs, itc.; but it has besides another mode of growth and decay equally singular. These plates form upon a vascular substance, not immediately ruiliering to the lower jaw-bone, but having a more (lenge substance between, which is also vascular. This substance, which may be called the nidus of the whalebone, sends out (the above) thin broad processes, answering to each plate, on which the plate is formed, as the cock's spur or the bull's horn, on the bony core, or a tooth on its pulp; so that each plate is necessarily hollow at its growing end, the first p>ar•t of the growth taking place on the inside of this hollow. Bolide:, this mode of growth, which is common to all such substances, it receives additional layers on the outside, which are formed from the above-mentioned vascular substance extended along the surface of the jaw. This part also forms upon it a semi-horny substance between each plate, which is very white, rises with the whalebone, and becomes even with the outer edge of the jaw, and the termi nation of- its outer part forms the bead above mentioned. This intermediate substance fills up the spaces between the plates as high as the jaws, acts as abutments to the whalebone, or is similar to the alveolar processes of the teeth, keeping them firm in their places. As both the whalebone and the intermediate substance are constantly growing, and as we must suppose a determined length necessary, a regular mode of decay must be established, not depending entirely on chance, or the use it is 'Jut to. In its growth three parts appear to be formed : one from the rising core, which is the centre ; a second on the outside ; and a third being the intermediate substance. These appear to have three stages of duration ; for that which forms on the core, I believe, makes the hair, and that on the outside makes princi pally the Plate of whalebone. This, when got a certain length, breaks off, leaving the hair projecting, becoming at the termination very brittle ; and the third or intermediate substance, by the time it rises as high as the edge of the skin of the jaw, decays and softens away like the old cuticle of the sole of the foot when steeped in water. The use of whalebone, I should believe, is principally for the retention of the food till swallowed; and I suppose the fish they catch are small when compared with the size of the mouth." (Hunter On Whales.') or me 1\ ftaleoone. ',owes, • oueetograplly.•1 The following notes by Dr. J. E. Gray contain the result of the most recent observations on this curious production in the Cetacea :— " The baleen, or whalebone, has generally been considered as the teeth of the whale; but this must be a mistake, for Mr. Knox observes : the foetal B. mystic-etas GO to 70 dental pulps were found on each side of each jaw, making the whole number amount to from 260 to 300. The preparation (No. 56) exhibits a portion of this gum with 12 pulps. Had these pulps been confined to the upper jaw, and corresponded to the number of baleen plates, it would have formed a strong analogy between the baleen and teeth ; but the number of baleen plates in the whale greatly exceeds the number of dental pulps ; and the lower jaw, which contained an equal number of pulps with the upper, has neither teeth nor baleen in the adult whale. Their presence therefore in the forms one of the most beautiful illustrations of the unity of organisation in the animal economy. The teeth in the Bala-na never cut the gum, but become gradually re-absorbed into the system ; the very cavity in which the gums were lodged disappears ; whilst, to suit the purposes of nature, the integumentary system furnishes the baleen, which is evidently a modified form of hair and cuticle.' (Knox, Cat. Whales,' 22.) Pro fessor Eschricht has shown also that the foetus of Mcgaptera Beeps C Danish Trans.; xi. t. 4, 1845) has numerous teeth on the edge of the jaw, though they are never developed. I am inclined to regard the baleen as a peculiar development of hair in the palates of these animals, and somewhat analogous to the hair found in the palates of the genus Leptis.