,590 



CETACEA. 



the derm, and open in the intervals of the 

 papillae by an entice generally closed by a 

 small epidermic valve. 



4. The inhalent apparatus (Tappareil d 1 in- 

 halation) is formed by extremely delicate 

 canals, which are smooth, straight, silvery, 

 branched, and very easily ruptured : they 

 originate in a plexus extended in the dermis 

 beneath the sudorific canals, anastomose to- 

 gether, and are provided with partitions. The 

 lymphatic vessels have no connection with 

 these canals, which communicate directly with 

 the arteries and veins. They are absorbing 

 canals. 



5. The mucous apparatus (Vappareil blen- 

 nogene). This is composed of secerning 

 glands and excretory ducts, which open be- 

 tween the papillae like the orifices of the pre- 

 ceding canals. It is wholly contained in the 

 derm, and produces a mucous material, which 

 by desiccation (en se dessechant) becomes the 

 cuticle. In the Whales this cuticle acquires 

 an extreme thickness : it is much thinner in 

 the Dolphins. 



6. The colorific apparatus (Vappureil chro- 

 matogene) is likewise composed of secerning 

 glands and excretory ducts ; it is situated in 

 the first superior (peripheral) layers of the 

 corium on the right and left sides of the outlet 

 of the excretory ducts of the preceding appa- 

 ratus, and it pours out the coloured product 

 at the same point where the mucous matter is 

 excreted, where it stains it. 



[It may be questioned how far this expla- 

 nation satisfactorily accounts for the formation of 

 cuticle in animals living habitually under water. 

 The whole account is to be received with reserve, 

 and requires to be confirmed by further ob- 

 servations, especially as regards the reflexion 

 of the nervous fibrils and the sudorific and 

 inhalent apparatuses.] 



We do not stop to examine how far this 

 analysis serves to explain the different phe- 

 nomena which the external teguments of the 

 Mammalia present. But admitting it as it is 

 presented to us, it results that the sensations 

 of touch must be lively and delicate in the 

 Cetacea : the great development of their pa- 

 pillary apparatus leads to this conclusion. 

 Nevertheless, the most generally received opi- 

 nion is that the common Dolphin, notwith- 

 standing the delicacy of its epidermis, has but 

 little tactile sensibility. But is this opinion 

 devoid of foundation ? or is it explicable on 

 the ground of the deposition of fat, which 

 penetrates every part of the skin, and is accu- 

 mulated in a dense layer beneath it, so as to 

 enfeeble the sensibility of the surface, accord- 

 ing to the common belief. This is the opinion 

 to which we have arrived. With respect to 

 the Balaenidae no difficulty exists on account 

 of the thickness and horny texture of the epi- 

 dermis. 



[According to Hunter's views the reticular 

 network containing the blubber, which he de- 

 scribes as fine in the Porpoise, Spermaceti, 

 and large Whale-bone Whale ( Balcena), and 

 coarse in the Grampus and small Whale-bone 

 Whale ( Balifiioptcra), forms part of the skin; 



for he observes that " the cutis seems to be 

 the termination of the cellular membrane of 

 the body more closely united, having smaller 

 interstices and becoming more compact," and 

 that the distinction between the skin and cel- 

 lular membrane is much less obvious in fat 

 than in lean animals; " for the cells of both 

 membrane and skin being loaded with fat, the 

 whole has more the appearance of one uniform 

 substance. This uniformity of the adipose 

 membrane and skin is most observable in the 

 Whale, Seal, Hog, and the Human Species."*] 



In the Baltfnopterce the integument covering 

 the ventral surface of the neck, thorax, and 

 anterior part of the abdomen, is disposed in 

 longitudinal folds, about five-eighths of an 

 inch in breadth in the contracted state. The 

 skin is very soft in the insterstices of the folds, 

 and covered there with a thinner cuticle : it 

 possesses great elasticity over the whole of the 

 plicated surface. A panniculus carnosus ad- 

 heres closely to this part of the skin, but is 

 separated by a loose cellular membrane from 

 the deep-seated muscles ; in which space the 

 blubber is in smaller quantity than on the dorsal 

 and lateral parts of the body. 



Besides the adipose substance which is ac- 

 cumulated beneath the integument, another 

 secretion of a peculiar kind, called Sperma- 

 ceti, which is analogous in many of its pro- 

 perties to the adeps, is met with in certain 

 species of Cetacea, but more particularly in 

 the genera Catodon and Pht/seter, which are 

 hence termed Spermaceti Whales. Of this 

 substance Mr. Hunter gives the following 

 account from a dissection of a recent specimen 

 of one of these Whales. 



[ " What is called spermaceti is found every 

 where in the body in small quantity, mixed 

 with the common fat of the animal, bearing a 

 very small proportion to the other fat. In the 

 head it is the reverse, for there the quantity of 

 spermaceti is large when compared to that of 

 the oil, although they are mixed, as in the 

 other parts of the body. 



" As the spermaceti is found in the largest 

 quantity in the head, and in what would ap- 

 pear on a slight view to be the cavity of the 

 skull, from a peculiarity in the shape of that 

 bone, it has been imagined by some to be the 

 brain. 



" These two kinds of fat in the head are con- 

 tained in cells, or cellular membrane, in the 

 same manner as the fat in other animals ; but 

 besides the common cells there are larger ones, 

 or ligamentous partitions going across, the 

 better to support the vast load of oil, of 

 which the bulk of the head is principally 

 made up. 



" There are two places in the head where 

 this oil lies ; these are situated along its upper 

 and lower part : between them pass the nos- 

 trils, and a vast number of tendons going to 

 the nose and different parts of the head. 



" The purest spermaceti is contained in the 

 smallest and least .ligamentous cells : it lies 

 above the nostril, all along the upper part of 



* Ibid. p. 395. 



