180 BIVALVES. 



GENUS. ANOMIA.* 



ANOMIA, OR ANTIQUE LAMP. 



Generic character. Shell bivalve, inequivalve, 

 sub orbicular ; one valve flattened, and often 

 perforated near the apex, the other more con- 

 cave, and sometimes having its beak produced 

 and curved over the hinge ; hinge toothless, 

 having a linear projection which is united under 

 the beak to the opposite valve by a strong liga- 

 ment. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



This genus contains a variety of shells mate 

 rially differing in their appearance. The perfo- 

 ration in one of the valves for the emission of a 

 ligament, by which the animal adheres to marine 

 substances, is, perhaps, the most general, but 

 not an invariable, characteristic. 



The Anomiae are now arranged in two princi- 

 pal groups, very clearly distinguished from each 

 other. The shells of one division retain the 

 name of Anomia, and very much resemble a 

 small oyster in their appearance ; like them they 

 are fixed and stationary, living and perishing on 

 the spot where the egg was first deposited. 

 They are attached by means of a bony appen- 



* Plate IX. figure 9; plate X. figure 1. 



