B. IT,] THE IIISTOEY OF ANIMALS. 73 



BOOK THE FOURTH. 



CHAPTER I. 



1. WE have hitherto treated of sanguineous animals, the 

 parts possessed by all as well as those which are peculiar to 

 each class, and of their heterogeneous and homogeneous, 

 their external and internal parts. We are now about to 

 treat of ex-sanguineous animals. There are many classes 

 of these, first of all the mollusca. 1 These are ex-sanguineous 

 animals, which have their, fleshy parts external, and their 

 hard parts internal, like sanguineous animals, as the whole 

 tribe of cuttle-fish. Next the malacostraca, these are 

 animals which have their hard parts external, and their in- 

 terior parts soft and fleshy; their hard parts are rather liable 

 to contusion than brittle, as the class of carabi and cancri. 



2. Another class is that of the testacea. These are ani- 

 mals which have their internal parts fleshy, and their ex- 

 ternal parts hard, brittle, and fragile, but not liable to 

 contusion. Snails and oysters are instances of this class. 



3. The fourth class is that of insects, which includes many 

 dissimilar forms. Insects are animals which, as their name 

 signifies, are insected either in their lower or upper part, or in 

 both ; they have neither distinct flesh nor bone, but something 

 between both, for their body is equally hard internally and 

 externally. There are apterous insects, as the julus and 

 scolopendra ; and winged, as the bee, cockchafer, and wasp ; 

 and in some kinds there are both winged and apterous in- 

 sects ; ants, for example, are both winged and apterous, 

 and so is the glowwor'n. 



4. These are the parts of animals of the class mollusca (ma- 

 lacia) ; first the feet, as they are called, next to these the 

 head, continuous with them ; the third part is the abdomen, 

 which contains the viscera. Some persons, speaking incor- 

 rectly, call this the head. The fins are placed in a circle 

 round this abdomen. It happens in many of the malacia 

 that the head is placed between the feet and the abdomen. 



1 The Cephalopoda. 



