"• I/- 55 



the projection of this part is quite invisible. The region exposed 

 by thus opening the mouth is spinous ; for it is formed by the 

 close apposition of the gills, which are of a spinous character. 



In crocodiles the immobility of the lower jaw also contributes 

 in some measure to stunt the development of the tongue. 

 For the crocodile's tongue is adherent to the lower jaw;^ and 

 its upper and lower jaws are as it were inverted, for in other 

 animals it is the upper jaw which is the immoveable one. The 

 tongue, then, of this animal does not adhere to the upper jaw, 

 because that would interfere with the ingestion of food, but 

 adheres to the lower jaw, because this is, as it were, the upper 

 one which has changed its place.^'' Moreover it is the crocodile's 

 lot though a land animal to live the life of a fish, and this 

 again necessarily involves an indistinct formation of the part in 

 question.^^ 



The roof of the mouth resembles flesh, even in many of the 

 fishes ; and in some of the river species, as for instance in the 

 fishes known as Cyprini,^^ is so very flesh-like and soft as to be 

 taken by careless observers for a tongue. The tongue of fishes, 

 however, though it exists as a separate part, is never distinctly 

 visible like this, as has been already explained. Again, as the 

 gustatory sensibility is intended to serve animals in the selection 

 of food, it is not diffused equally over the whole surface of the 

 tongue-like organ, but is placed chiefly in the tip ; ^' and for 

 this reason it is the tip which is the only part of the tongue 

 separated in fishes from the rest of the mouth. As all animals 

 are sensible to the pleasure derivable from food, they all feel a 

 desire for it. For the object of desire is the pleasant. The part 

 however in which food produces the sensation is not precisely alike 

 in all of them, but while in some it is free from attachments, in 

 others, where it is not required for vocal purposes, it is united with 

 the base of the mouth ; in some again it is hard, in others soft 

 or flesh-like. Thus even the Crustacea,^* the Carabi for instance 

 and the like, and the Cephalopods, such as the Sepias and the 

 Poulps, have some such part inside the mouth. As for the 

 Insects, some of them have the part which serves as tongue 

 inside the mouth, as is the case with ants, and as is also the 

 case with many Testacea, while in others it is placed externally. 

 In this latter case it resembles a sting or piercer, and is 

 hollow and spongy, so as to serve at one and the same time for 

 661a. 



