60 CONCHOLOGY. 
C. medinum. C. fragum. 
C. tumotiferum. C. lineatum. 
C. retusum. C. edule. 
C. rusticum. C. latum. 
C. Greendlandicum. ’ C. exigunum. 
C. crenulatum, C. rosenum. 
C. minotum. C. hemicardium. 
C. scobinatum. . Junonie. 
C. cardissum. . muricatum. 
(er il a. 
C. inversum. C. marmoreum. 
C. ventricosum. ©. sulcatum. 
C. obtusum. C. cifidium. 
C. Mortonii.* C. Californianum.* 
C. quadragenarium.* 
C. Pennulatum.* 
C. substriatum.* 
C. Nuttallii* 
C. pubescens.* 
2. Genus Cardita. YI. VII. 
Animal. 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 
branchie 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, lamellous 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. 
C. squamosa. 
C. crassicosta. 
C. calyculata. 
C. nodulosa. 
C. trepezia. 
Cardita sulcata. 
C. turgida. 
C. phrenetica. 
C. rufescens. 
C. subaspera. 
C. intermedia. 
