148 THE ANIMAL KINGDOM. 



generally attached to the rocks in, or at the side of, the 

 water, and they seize their prey by means of two arms, 

 which they can protrude to a considerable distance from 

 their shell, and can draw them in again at pleasure. 

 Conchifera* are molluscous animals, which are entirely 

 encased in bivalve shells ; they have no apparent head, and 

 are therefore called "acephalous," or headless. These 

 animals are most important, as they furnish not only an 

 immense quantity of food, but also supply the valuable 



a. Hinge. 



b. Liver. 



c. Lips. 



d. Shell. 



e. Mantle. 



f. Stomach. 



g. Gills. 

 h. Heart. 



i. Intestine. 



Fig. io 3 .-THE OYSTER. 



articles known as Pearls. These are found in the mantles 

 of several shell-fish, but principally in those of the 

 Pearl- Oyster. It is scarcely necessary to describe 

 the Common edible Oyster: an engraving (Fig. 103) is 

 annexed, from which you will see the position of the various 

 organs. We receive the finest Pearls and the shells of the 

 pearl-oyster, which is called " mother of pearl," from the 



* Cone/la, a shell ; fero, I carry. 



