CONCHIFERA. 



245 



for the passage of a lanceolate foot ; siphons short, united, 

 unequal, the branchial largest, both bearing a few long, 

 filiform cirrhi at their skies, extending beyond the orifices 

 anal siphon with a very extensile membranous valve 3* 

 — 22 species ; also fossil. 



From the European seas. An English species, N. Cus- 

 pidata, is an elegantly formed shell, with a projecting beak, 

 almost semi-transparent, and with a silky epidermis : it is 

 rare. 



Poromya. Forbes, — Shell ovate, or suborbicular, equi- 

 valve, inequilateral, slightly produced posteriorly; surface 

 invested with a scabrous epidermis, beneath which it is 

 pearly and minutely punctured : hinge, a minute cardi- 

 nal erect tooth in one valve, lodged in a pit or impression 

 in the other ; no lateral teeth ; ligament external ; pallial 

 impression very slightly sinuated. Animal unknown, pro- 

 bably resembling Neozra, — Few species: also fossil. P. 

 granulata is British. 



Family 5. — MY A CEA, 



The animal has an almost entirely closed, often very 

 thick, and fleshy mantle ; two thick siphons united toge- 

 ther, but covered by a continuation of the epidermis ; foot 

 small ; the shell is often somewhat inequivalve, gaping very 

 widely on one or both sides; the ligament is sometimes 

 i external, sometimes internal. 

 Marine. ^^^^^^^ 



Lutraria. Lam. (Lutri- 

 cola Blain.). Shell equivalve^ 

 inequilateral, transverse, gaping \ 

 at both extremities; an erect 

 cardinal tooth in one valve 

 locking into a cavity in the 



* Forbes's British Moll, 



