B. VIII.] THE HISTORY OF ANIMALS. 197 



creatures are sanguineous. The nature of the malacia and 

 malacostraca is the same ; for these swallow water for 

 food. 



5. Those animals which breathe air, but live in the water, 

 and those which breathe water, and have gills, but go out 

 upon dry land and take their food there, belong to two divi- 

 sions of aquatic animals. This last division is represented 

 by a single animal called the cordylus (water newt) ; for 

 this animal has no lungs, but gills ; and it goes on dry land 

 to procure its food. It has four feet, so that it appears na- 

 tural that it should walk. In all these animals nature ap- 

 pears to be, as it were, turned aside, and some of the males 

 appear to be females, and the females have a male appear- 

 ance ; for animals which have but small diversity in particular 

 parts, exhibit great variations in the whole body. 



6. This is evident in castrated animals ; for if a small 

 portion only of the body is destroyed, the animal becomes 

 a female ; so that it is plain that if a very minute portion 

 in the original composition of an animal becomes changed, 

 if that portion belongs to the origin of the species, it might 

 become either male or female ; or, if taken away altogether, 

 the animal might be neuter. And so, either way, it might 

 become a land or aquatic animal, if only a small change took 



place it happens that some become terrestrial and 



others aquatic animals, and some are not amphibious which 

 others are, because in their original generation they received 

 some kind of substance which they use for food. For that 

 which is natural is agreeable to every animal, as I have said 

 before. 



CHAPTER III. 



1. "WHEN animals are divided in three ways into aquatic 

 and land animals, because they either breathe air or water, 

 or from the composition of their bodies ; or, in the third 

 place, from their food, their manner of life will be found to 

 agree with these divisions. For some follow both the com- 

 position of their bodies and the nature of their food, and 

 their respiration of either water or air. Others only agree 

 with their composition and food. 



2. The testacea which are immpveable live by a fluid 

 which percolates through tne dense parts of the sea, and 



