MOLLUSCA. 



Cardium C^i' iisja. 



Variegated Ampliidesma. 



ilium Elongatum. 



the ligament is external. Animals of this class affix themselves to other bodies by a particular 

 muscle, which is protruded through the gaping part of the valves. When young, they also adhere by the 

 byssiform epidermis, which envelops the exterior. 



The Cardium Cardissa belongs to the cockle family of the headless, bivalve molluscs. Of this family 

 the general characteristics are, that the mantle is open in front, but behind presents two syphons, or ori- 

 fices, one for breathing, and the other for passing egesta. These syphons are sometimes distinct, and 

 sometimes massed together. At either end of the shell is a transverse adductor, and a foot for the general 

 purpose of locomotion. As a general rule, the species, with elongated syphons, live buried in the mud or 

 sand. The plate annexed represents the Cardium Cardissa, a spotted variety of the family, a3 of the 

 natural size. 



The Cardium Elongatum, another variety of the same family, so resembles the preceding in its general 

 features, as to require no separate description. The character of its valves and hinge may be seen in the 

 appended cut. 



The Brazilian Capsa belongs to a genus, in which the hinge closely resembles that of the Cardium, but 

 the shell nearly approaches the triangular, with the obtuse angle at the umbones of the valves, and the 



Common Craseatclla. 



Donax Scortum 



(375) 



-*~JU 



