50 



EAST COAST MARINE SHELLS 



often less. Depth range 2-182 fathoms. 



A frequent shell upon the West 

 Indian beaches, especially in the Bahamas. 



PI. 17, Fig. 10 



Florida Strait and West Indies 



TRIGONICAEDIA CERAMIDUM Dall. Ribs eight- 

 een in number, the four middle much larger 

 in proportion to the others. Alt. of large 

 example 8.2 mm. Color yellowish. Off 

 Havana it was taken in 182 fathoms. 



PI. 62, Fig. 6 



Florida Strait; West Indies 



SUBGENUS AMERICARDIA Stewart 1930 



TRIGONIOCARDIA MEDIUM Linnfe. Shell inequi- 

 lateral, solid; about thirty-five strong 

 almost smooth ribs; ten ribs upon posteri- 

 or end rounded and with deep grooves be- 

 tween, the remainder overhanging the deep 

 grooves; teeth strong; color white or buff, 

 touched with brown or purple. Height 85 run. 

 Florida examples 1 inch. 



A young example was dredged in 

 shallow water of Card Sound, Florida. It 

 usually prefers deeper water but single 

 valves are often foimd on the beaches of 

 the Florida Keys. 



PI. 17, Fig. 5 



Cape Hatteras, North Carolina to 



the West Indies 



GENUS LAEVICARDIUM Swainson 1840 



LAEVICARDIUM SERRATUM Linn6. Saw- toothed 

 Cockle. Surface nearly smooth, polished, 

 creamy white, suffused with a golden tint, 

 often pink toward umbones; faint traces of 

 ribs; posterior edge less curved than an- 

 terior; scarcely gaping, delicately toothed 

 on margin; lateral teeth high and prominent, 

 cardinal teeth small. Height 1-2 inches. 



A specimen dredged by the author 

 in Lower Biscayne Bay, Florida, by wield- 

 ing its powerful foot suddenly leaped from 

 its captor's hand. 



PI. 17, Fig. 7 



Cape Hatteras, North Carolina to 



the West Indies. 



LAEVICARDIUM SERRATUM LAEVIGATUM Lamarck, 

 Shell rather large, usually but not always 

 faintly ribbed, ribs numerous when present 

 but most apparent toward margin of shell, 

 areas at ends smoother often than remainder 



of shell and emphasized by a lunule-like 

 area outlined with a shallow groove; ante- 

 rior lateral teeth strongest; interior mar- 

 gin of shell toothed. Color whitish, cream 

 or pale brown with touches of brown. Height 

 2 inches. 



Usually larger than the typical 

 form, not so polished, brown bands more 

 prominent. Upon the Florida west coast 

 this is an outstanding form. 



Florida; West Indies 



LAEVICARDIUM MORTONI Conrad. Morton's 

 Cockle. A comparatively smooth little 

 shell with a purple spot on posterior mar- 

 gin; interior bright yellow. Height 1 inch 

 or less. 



Most plentiful in Long Island Sound 

 and region of Martha's Vineyard. It lives 

 in 1-5 fathoms of water in the north. Bril- 

 liantly colored examples were dredged in 

 the muddy waters of Tarpon Bay, Sanibel, 

 Florida. The colors of this species ap- 

 pear to fade rapidly in the cabinet. 



PI. 17, Fig. 4 



PI. 75, Fig. 8 



Nova Scotia southward to Brazil 



GENUS SERRIPES Beck 1841; 

 Aphrodite Lea 1834, not Hubner 1816 



SERRIPES GROENLANDICUS Bruguiere. Shell 

 large, surface with many radiating ridges 

 which are coarsest at the posterior end; 

 margin extending beyond the ligament; um- 

 bones insignificant, curved inward and a 

 little forward, almost in center of shell; 

 epidermis thin, pale brown, shining; car- 

 dinal teeth almost absent, lateral teeth 

 small but distinct. Length under 3 inches. 



The serrated margin of the animal's 

 foot has suggested the name for the genus. 

 The shell is remarkable for a decided gape 

 at the posterior end, also for its resem- 

 blance to Mactra. Depth range 2-260 fath- 

 oms. 



PI. 16, Fig. 7 



Greenland to Cape Cod, Massachusetts 



GENUS PROTOCARDIA Beyrich 1845 



PROTOCARDIA PERAMABILIS Dall. A small 

 plump shell with high subcentral umbones; 

 anterior end evenly rounded, the posterior 

 somewhat truncate; surface with numerous 

 radiating lines crossed by concentric 



