PARTS OF ANIMALS, IV. xi. 



and some no feet at all. Actually there is only one 

 group that has no feet, the Serpents ; and the reason 

 why they have none has been stated in my treatise on 

 the Locomotion of Animals."• In other respects their 

 conformation is similar to that of the oviparous 

 quadrupeds. 



These animals have a head, and the parts that com- 

 pose it, for the same reasons that other blooded 

 creatures have one, and they have a tongue inside the 

 mouth — all except the river crocodile, Λvhich appar- 

 ently has none, but only a space for it ; and the reason 

 is that in a Λvay he is both a land-animal and a water- 

 animal. In virtue of being a land-animal, he has a 

 space for a tongue ; as a water-animal, he is tongue- 

 less. This agrees with our previous statement,'' that 

 some fishes appear to have no tongue unless you pull 

 the mouth very well open, others have one which is 

 not distinctly articulated. The reason for this is that 

 these creatures have not much need for a tongue 

 because they cannot chew their food or even taste 

 it before they eat it : they can perceive the pleasant- 

 ness of it only while they are swallowing it. This 

 is because the perception of juices is effected by the 

 tongue ; whereas the pleasantness of solid food is 

 perceived Avhile it is passing down the gullet, and 

 thus oily food and hot food and the like are per- 

 ceived while they are being swallowed. Of course 

 the Vivipara as well as these creatures have this 

 power of perception (indeed, the enjoyment derived 

 from practically all edible dainties takes place while 

 they are being sAvallowed and is due to the distension 

 of the oesophagus — Avhich is why intemperate ap- 

 petite for edible dainties is not found in the same 

 animals as intemperate appetite for drink and juices) ; 



393 



