PARTS OF ANIMALS, IV. xi. 



but whereas the rest of the animals have the power of 

 perception b}^ taste as well, these are without it 

 and possess the other one only. Among oviparous 

 quadrupeds, lizards (and serpents too) have a two- 

 forked tongue, the tips of which are as fine as hairs. 

 (This has been stated earher.") Seals also have a 

 forked tongue. This forked tongue explains why all 

 these animals are so dainty in their food. 



The four-footed Ovipara also have sharp interfitting 

 teeth, as Fishes have. Their sense-organs are all 

 similar to those of other animals : nostrils for smell, 

 eyes for sight, and ears for hearing — though their ears 

 do not stand out : they are merely a duct, as in 

 birds ; and in both groups the cause is the same, viz. 

 the hardness of their integument. Birds are covered 

 with feathers, and these creatures are all covered 

 with horny scales which correspond in position to the 

 scales of fishes, but are harder in substance. This 

 is clearly illustrated by the tortoises, the great snakes, 

 and the river crocodiles, where the scales are made of 

 the same material as the bones and actually grow 

 stronger than the bones. 



These animals, like birds, have no upper eyelid ; 

 they close their eyes with the lower lid. The reason 

 which was given ^ for birds applies to them too. Some 

 birds can also blink by means of a membrane which 

 comes out of the corner of the eye ; but these 

 animals do not do this, since their eyes are harder 

 than birds' eyes. The reason for this is that keen 

 sight is of considerable use to birds in their daily 



«• At 660 b 9. ^ At 657 b 6 ff. 



^ At'xva Karsch : laxva vulg. 



* O^VCOTTLa Kal TO TTOppOJ TTpo'CBe'iv UY. 



395 



