PARTS OF ANIMALS, II. xvii. 



Among the factors which contribute to the de- 

 formity of the crocodile's tongue is the immobihty 

 of its lower jaw, to which the tongue is naturally 

 joined. We must remember, however, that the 

 crocodile's jaws are topsy-turvy ; the bottom one is 

 on top and the top one below ; this is clearly so, 

 because in other animals the top jaw is the immovable 

 one. The tongue is not fixed to the upper jaw (as 

 one might expect it to be) because it would get in 

 the way of the food as it entered the mouth, but to 

 the lower one, which is really the upper one in the 

 wrong place. Furthermore, although the crocodile 

 is a land-animal, his manner of life is that of a fish, 

 and this is another reason why he must have a tongue 

 that is not distinctly articulated. 



Many fish, however, have a fleshy roof to their 

 mouths. In some of the fresh-water fish — e.g. 

 those known as Cyprinoi — it is very fleshy and soft, 

 so that casual observers think it is a tongue. In 

 fish, however, for the reason already given, the 

 tongue, though articulated, is not distinctly so ; yet, 

 inasmuch as the power also of perceiving tastes 

 resides in the tongue-like organ, though not in the 

 whole of it equally but chiefly in the tip, therefore on 

 this account in fish the tip only is separate from the 

 jaw. 



Now all animals are able to perceive the pleasant 

 taste which is derived from food, and so they have a 

 desire for food, because desire aims at getting that 

 which is pleasant. The part, however, by which this 

 perception or sensation of the food takes place, is 

 not identical in all of them, for some have a tongue 

 which moves freely and loosely, others (which have no 

 vocal functions) have a tongue that is fastened down. 



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