CONCHOLOGY. 41 



A. longirostris. A. myalis. 



A. globulosa. A. rupicola. 



A. Leana.* A. papyracea. 



FAMILY V. 



Mactbacea. Seven genera. 



1. Genus Liitraria. PI. VI. 



Animal. Body oval, much compressed, or subcylindrical ; 

 the mantle enclosed only in the half of its inferior side : foot 

 small and projecting but little beyond the abdominal mass, tubes 

 long, distinct or united. This genus is perfectly distinct from 

 the Mactra, to which it formerly belonged, on account of its 

 having no lateral teeth. It is called by De Blainville, Lutricola, 

 from its being found very deep in mud or sand at the mouth of 

 rivers. 



Shell. Oval or elongated, regular, equivalve, more or less 

 inequilateral, sometimes but slightly gaping : edges always simple 

 and trenchant ; summits feebly marked ; hinge subsimilar, formed 

 by two very small divergent cardinal teeth ; two very distinct 

 muscular impressions united by a palleal impression profoundly 

 sineous to the rear. Inhabits the seas of Europe and America. 

 Fourteen species. 



Lutraria solenoides. Lutraria elliptica. 



L. rugosa. L. papyracea. 



L. compressa. L. plicatella. 



L. piperata. L. crassiplica. 



L. tellinoides. L. complanata. 



L. Candida, 



L. lineata.* L. Nuttallii.* 



L. caniculat?i.* 



2. Genus Mactra. PI. VI. 



Animal. Body oval and pretty thick ; edges of the mantle 



4*"' 



