46 POPULAR CONCHOLOGY. 



1. Brachiopoda. * 2. Dimyaria.f 3. Mono- 

 myaria. f . 



The component parts of a bivalve shell will 

 be understood by referring to the annexed re- 

 presentation., in which A A are the bosses, or 

 prominences, which exist near B, the hinge, or 

 juncture of the two valves ; the latter are also 

 kept together by strong muscles, which pro- 

 ceed from the animal itself, and are attached 

 to each valve on the interior surface. Under 

 the bosses, and inside the valves, are the 

 teeth, being little projections that lock into 

 each other, and serve to keep the valves steady 

 when closed ; they are divided into cardinal §, 

 or principal teeth, c ; and lateral ||, or side 



* From brachion, Gr., arm, and poda, feet, 



f From disy Gr., double, and my on, muscle. 



J From monos, Gr., single, and myon, muscle. 



§ From car do, a hinge, || From latus, a side. 



