VOL. LXXVII.] PHILOSOPHICAL TBANSACTIONS. 321 



The skin is extremely elastic in the greatest number of quadrupeds, and in its 

 contracted state may be said to be rather too small for the body; by this elasticity 

 it adapts itself to the changes which are constantly taking place in the parts ; 

 and it is for the want of it that it becomes too large in some old animals. In 

 all animals it is more elastic in some parts than others, especially in those where 

 there is the greatest motion. How far these variations take place in the whale I 

 do not exactly know; but a loose elastic skin in this tribe would appear to be im- 

 proper as universal covering, considering the progressive motion of the animal, 

 and the medium in which it moves ; it therefore appears to be kept always on the 

 stretch, by the adipose membrane being loaded with fat, which does not allow 

 the skin to recede when cut. It is however more elastic at the setting on of the 

 eyelids, round the opening of the prepuce, the nipples, the setting on of the 

 fins, and under the jaw, to allow of motion in those parts; and here there is 

 more reticular, and less adipose membrane. But in the piked whale there is 

 probably one of the most striking instances of an elastic cuticular contraction: 

 for though the whole skin of the fore part of the neck and breast of the animal, 

 as far down as the middle of the belly, be extremely elastic; yet to render it still 

 more so, it is ribbed longitudinally like a ribbed stocking, which gives an in- 

 creased lateral elasticity. These ribs are, when contracted, about -f- of an inch 

 broad, covered with the common skin of the animal ; but in the hollow part of 

 the rib, it is of a softer texture, with a thinner cuticle. This part is possessed 

 of the greatest elasticity: but why it should be so elastic is difficult to say, as it 

 covers the thorax, which can never be increased in size; yet there must be some 

 peculiar circumstance in the economy of the species requiring this structure, 

 which we as yet know nothing of The skin is intended for various purposes. 

 It is the universal covering given for the defence of all kinds of animals; and 

 that it might answer this purpose well, it is the seat of one of the senses. 



Of the mode of catching their food. — The mouths of animals are the first 

 parts to be considered respecting nourishment or food, and are so much con- 

 nected with every thing relative to it, as not only to give good hints whether the 

 food is vegetable or animal, but also respecting the particular kind of either, 

 especially of animal food. The mouth not only receives the food, but is the 

 immediate instrument for catching it. As it is a compound instrument in many 

 animals, having parts of various constructions belonging to it, I shall at present 

 consider it in this tribe no further than as connected with their mode of catching 

 the food, and adapting and disposing it for being swallowed. It is probable that 

 these animals do not require either a division of the food, or a mastication of it 

 in the mouth, but swallow whatever they catch, whole ; for we do not find any 

 of them furnished with parts capable of producing either effect. The mouth in 



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