320 PHILOSOPHICAL TRANSACTIONS. [aNNO J 787. 



Of the skin. — The covering of this order of animals consists of a cuticle and 

 cutis. The cuticle is somewhat similar to that on the sole of the foot in the 

 human species, and appears to he made up of a number of layers, which se- 

 parate by slight putrefaction ; but this I suspect arises in some degree from there 

 being a succession of cuticles formed. It has no degree of elasticity or tough- 

 ness, but tears easily; nor do its fibres appear to have any particular direction. 

 The internal stratum is tough and thick, and in the spermaceti whale its internal 

 surface, when separated from the cutis, is just like coars^. velvet, each pile 

 standing firm in its place; but this is not so distinguishable in some of the 

 others, though it appears rough from the innumerable perforations. It is the 

 cuticle that gives the colour to the animal ; and in parts that are dark I think I 

 have seen a dirty coloured substance, washed away in the separation of the cu- 

 ticle from the cutis, which must be a kind of rete mucosum. 



The cutis in this tribe is extremely villous on its external surface, answering 

 to the rough surface of the cuticle, and forming in some parts small ridges, 

 similar to those on the human fingers and toes. These villi are soft and pliable; 

 they float in water, and each is longer or shorter according to the size of the 

 animal. In the spermaceti whale they were about a quarter of an inch long; in 

 the grampus, bottle- nose and piked whales, much shorter; in all, they are ex- 

 tremely vascular. The cutis seems to be the termination of the cellular mem- 

 brane of the body more closely united, having smaller interstices, and becoming 

 more compact. This alteration in the texture is so sudden as to make an evident 

 distinction between fvhat is solely connecting membrane, and skin, and is most 

 evident in lean animals; for in the change from fat to lean, the skin does not 

 undergo an alteration equal to what takes place in the adipose membrane, though 

 it may be observed, that the skin itself is diminished in thickness. In fat ani- 

 mals the distinction between skin and cellular membrane is much less, the gra- 

 dation from the one to the other seeming to be slower; 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; and is not 

 only visible in the raw but in the dressed hides; for in dressed skins the external 

 is much more compact in texture than in the inner surface, and is in common 

 very tough. 



In some animals the cutis is extremely thick, and in some parts much more so 

 than others : where very thick, it appears to be intended as a defence against the 

 violence of their own species or other animals. In most quadrupeds it is mus- 

 cular, contracting by cold, and relaxing by heat. Many other stimulating sub- 

 stances make it contract; but cold is probably that stimulus by which it was 

 intended to be generally affected. 



