GIIA&D DIVISIONS. it 



sensible and furnished with a liquid humor 

 issues from its pore*. 



Molluscous animals are generally covered with 

 plates of carbonate of lime, which serve as beds 

 er retreats from danger. These plates, usually 

 called shells, are produced by secretion from the 

 skin. The process of reproduction greatly re- 

 sembles that of plants with perfect flowers ; rare- 

 ly that of dioecious flowers. 



Animals of this division, though more compli- 

 cated in their digestive and circulatory system 

 than animals of the articulated division,* seem 

 to have been cotemporaries with the oldest of 

 the radiated division. For we find the remains 

 of several species of this division in the oldest 

 transition rocks, which rarely if ever, contain any 

 relics of the articulated or vertebral divisions. 



Examples. Nautilus, snails, oysters, barni- 

 eles. 



III. ARTICULATED ANIMALS. 



In this division the sentient principle is lodged 

 in two lon^ cords, swelling at intervals into knots 

 or ganglyous, extending through a jointed body 

 in the longitudinal direction. The organs of sense 

 and motion are all double, and arranged on two 

 sides of the nervous axis. 



The principal ganglyon is placed near the 

 throat. They have jointed trunks or abdomens j 

 and all but one class, have jointed limbs articula- 



* Cuvier places this division between the vertebral and articulated, 

 on account of the greater perfection of the residence of the sentient 

 principle. For if the bee is more active than the oyster, so the cat 

 and pigeon are more active than man. But we have changed the or- 

 der to accommodate it to the study of petrifactions and shells ; for very 

 few have the means for studying the anatomical structure of 

 ceous animals. 



