EAST COAST MARINE SHELLS 



49 



PI. 17, Fig. 3 



Cape Hatteras, North Carolina to 



West Indies 



CARDIUM MURICATUM Linn§. Ribs thirty to 

 forty, each with a row of solid oblique low 

 scales; color whitish, buff or brownish, 

 sometimes variegated; interior light, of- 

 ten marked or streaked with purple. Height 

 25 mm. 



A common shell on the Florida west 

 coast beaches. 



PI. 17, Fig. 1 



Cape Hatteras, North Carolina to 



West Indies 



SUBGENUS CERASTODERMA Morch 1853 



CARDIUM CILIATUM Fabricius (C. islandicum 

 Lam.). Iceland Cockle. A rather large 

 thin shell; anterior end shortest and nar- 

 rowest; umbones prominent, pointing inward 

 and almost touching each other; about 

 thirty-six sharp three-sided ribs; epider- 

 mis yellowish brown with a bristling fringe; 

 interior straw colored, portion covered by 

 mantle pearly; inside grooves correspond- 

 ing to ribs without, margins strongly 

 notched; ribs well separated and with a 

 tendency toward angularity. Height 2 inch- 

 es; breadth 1 inch. 



A plentiful shell in moderate 

 depths off the New England coast. It is 

 often found in the stomachs of fish. 



PI. 17, Fig. 6 



Arctic Sea to Cape Hatteras, North 



Carolina 



CARDIUM PINNULATUM Conrad. Pointed Edge 

 Cockle. Shell small, fragile, thin, 

 obliquely orbicular; about twenty-six ribs 

 which become convex at base, crossed by 

 evenly placed flattened scales; umbones a 

 little raised and inclined inwards; color 

 dirty white or yellowish. Length 12 mm. 



PI. 20, Fig. 11 



PI. 73, Fig. 5 



Labrador to Cape Lookout, North 



Carolina 



SUBGENUS DINOCARDIUM Dall 1900 



CARDIUM ROBUSTUM Solander. (C. magnum L.) 

 Strong Cockle. Ribs thirty- three to thir- 

 ty-seven, regularly arranged; color yel- 

 lowish brown with rows of chestnut or pur- 



ple spots; posterior area brownish purple. 

 Height 4 inches or more. 



The largest and handsomest of our 

 eastern cockles and an abundant one on the 

 Florida west coast. 



PI. 17, Fig. 2 



North Carolina to Brazil 



GENUS PAPYRIDEA Swainson 1840 



PAPYRIDEA SPINOSUM Meuschen. Spiny Paper 

 Cockle. Shell elongate, compressed, often 

 gaping, characterized by ribs which are in- 

 conspicuous in the center of the valves 

 but raised and provided with spines toward 

 the extremities, some of the spines extend- 

 ing over the margin; ligament area provid- 

 ed with deep grooves; exterior and interior 

 mottled with lavender or yellow. 



This delicately beautiful shell is 

 sometimes taken at Sanlbel where it at- 

 tains a length of 1 inch. At Yamato, on 

 the Florida east coast, specimens are 

 smaller. 



PI. 17, Fig. 8 



Cape Hatteras, North Carolina to 



Brazil 



PAPYRIDEA SEMISULCATA Gray. Shell whitish 

 yellow with broad, low, radiating ribs, 

 about twenty of these prominent, addition- 

 al and less conspicuous ribs toward anteri- 

 or end; posterior end with beautifully in- 

 dented margin, the portion adjacent to the 

 ligament finely so; exterior dull, the in- 

 terior glossy and showing the external 

 ribs. Length 8-14 mm. 



It has been taken in drift in Palm 

 Beach County, Florida. 

 PI. 17, Fig. 9 

 PI. 10, Fig. 15 



Palm Beach County, Florida; else- 

 where? 



GENUS TRIGONICARDIA Dall 1900 



A genus confined to Middle America, 

 both coasts. The name indicates the pe- 

 culiar form of the shell. 



TRIGONICARDIA ANTILLARUM Orbigny. Shell 

 trigonal in shape, bluntly keeled behind; 

 about twenty-three broad, low radiating 

 ribs which are more or less nodulous, the 

 interspaces much narrower; lateral teeth 

 strong, the cardinals small. Length 20 mm.. 



