NOMENCLATURE, 47 



Strlt:. See above. 



ahhreviatce. Abbreviated ; not extending to the 

 margin. 



hifarice. Bifarious; diverging. 



recurvatcB, Recurved; elevated, membranace- 

 ous, tending towards the apex. 



iiicequilineatce. Insequilinear ; not parallel. 



Sulci. See above; sometimes they signify the 

 same as Cos tee, Ribs. 



fornicati. Arched ; covered with arched scales. 



Testa. See above. 



antiquata. Antiquated; longitudinally sulcate or 

 furrowed, but interrupted by transverse 

 accretions, as if lesser valves were periodi- 

 cally added to the apex or beak. 



aurita. Eared; the hinge produced on either 

 side the beaks into a flat prominent an- 

 gle. 



bar lata. Bearded ; superficially covered with 



rigid hairs. 

 compressa. Compressed; the valves flattened, 



and the bosses less than usually gibbous. 

 dorsata. Dorsal; the back obtusely keeled.. 



