HINNITES. 555 



anterior one with a slight sinus. Hinge-line angulated ; 

 ligament linear ; cartilage-pit central. Muscular impression 

 sub-central, large ; pallial line simple. 



Syn. Amusium, Muhlf. Pleuronectia, Swains. 



Ex. A. pleuronectes, Linnaeus, pi. 127, fig. 3, 8, a. 



The species of this genus are few in number, and are 



inhabitants of the Indian seas, and the coast of North 



America. 



Species of Amussittm. 



caurinum Gould. obliteratum, Lam. 



Japonicum, Gmel. orbiculare, Sow. 



Laurentii, Gmel. pleuronectes, Linn. 

 Magellanicum, Gmel. 



Genus HINNITES, Defiance. 



Shell oval, irregular, inequivalve, closed, adherent by 

 the right valve ; surface of right valve irregular, of left 

 valve longitudinally grooved or scaly; auricles unequal, 

 the posterior the larger, with a sinus in the right one. 

 Hinge-margin straight; ligament long, narrow; cartilage- 

 pit central. Muscular impression very large and rounded ; 

 pallial impression strongly marked, entire. 



Syn. Hinnita, Gray. 



Ex. H. pusio, Linnaeus, pi. 127, fig. 4, 4, a. 



In this genus the lower valve of the shell in tbe adult 

 state is attached to foreign bodies, and becomes irregular. 

 One species is met with on the coasts of Britain, tbe 

 others are from Western America. 



Species of Hinnites. 



giganteus, Gray. pusio, Linn. 



Poulsoni, Conr. 



