60 



CONCHOLOGY. 



C. medinum. 



C. tumotiferum. 



C retusum. 



C. rusticum. 



C. Greendlandicum. 



C. crenulatum. 



C minotum. 



C. scobinatum. 



C. cardissum. 



C. inversum. 



C. ventricosum. 



C. obtusum. 



C. fragum. 

 C. lineatum. 

 C. edule. 

 C latum. 

 C. exigunum. 

 C rosenum. 

 C. hemicardiujn. 

 C. Junoniae. 

 C. muricatum. 

 C. marmoreum. 

 C. sulcatum. 

 C. cifidium. 



C. Mortonii.* 

 C. substriatum.' 

 C. Nuttallii.* 



C. pubescens. 



C Californianum.* 

 C. quadragenarium.* 

 C. Penriulatum.* 



2. Genus Cardita.^ PI. VII. 



.hiimal. Body suborbicular, terminated superiorly by a sort 

 of hook; mantle but little open; foot terminated at its extremity 

 by a part much narrower than the base ; superior lobes of the 

 branchiae very short. 



Shell. Thick, solid, equivalve, more or less inequilateral ; sum- 

 mit dorsal always much flexed anteriorly ; hinge similar, formed 

 by two oblique teeth, one short, cardinal or apicial, the other 

 post-apicial, long, lameJlous and arcuated ; ligament elongated, 

 subexterior and inserted ; two very distinct muscular impressions, 

 united by a palleal band, narrow and semicircular. Inhabits the 

 Mediterranean and American seas. Twenty-three living species. 

 Four fossil. 



Cardita Ajar. Cardita sulcata. 



C. squamosa. C. turgida. 



C. crassicosta. C. phrenetica. 



C. calyculata. C. rufescens. 



C nodulosa. C subaspera. 



('. trepezia. C. intermedia. 



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