PARTS OF ANIMALS, III. xiv. 



it alone ruminates, for horned animals which have no 

 teeth in the upper jaw also ruminate. All teeth in fish 

 are sharp ; this enables them to bite up their food, 

 though somewhat unsatisfactorily ; this is because 

 they cannot spend long over mastication ; hence 

 they neither have flat teeth nor may they grind 

 the food down ; therefore it would be idle to have 

 the teeth. Furthermore, some fishes have no gullet 

 at all, others have a short one ; but, in order to as- 

 sist the process of concoction, some of them, hke the 

 Kestreus,^ have fleshy stomachs, similar to those of 

 birds ; the majority, however, have a large number 

 of appendages ^ by the side of the stomach, in which 

 to store up the food as it might be in additional cellars 

 and there putrefy it up and concoct it. The ap- 

 pendages of fishes are, however, quite different from 

 those of birds. In fishes they are fairly high up 

 beside the stomach, whereas when present in birds 

 they are down below at the end of the gut. Some 

 of the V ivipara also have appendages ^ of this latter 

 kind, and their purpose is the same. 



The whole race of fishes is gluttonous for food, 

 because their equipment for reducing it is defective, 

 as a result of which most of it passes through un- 

 concocted. Of all, those which have a straight intes- 

 tine are especially gluttonous, since the food passes 

 through quickly, which means that their enjoyment 

 of it is brief, and therefore in its turn the desire for 

 food must come on again very quickly. 



I have already said that in animals with front 

 teeth in both jaws the stomach is small. These 

 stomachs fall into two main classes. Some have a 

 stomach resembUng that of the dog, some that of 



" 295 



