EAST COAST MARINj; SHELLS 



53 



Sarasota Bays, Florida. 

 PI, 19, Fig. 10 

 West Florida 



Length 18 mm. 



SUBGENUS HYSTEROCONCHA Fischer 1887 



Shell plump, concentric lines prom- 

 inent and a portion sharply upright j lu- 

 nula and escutcheon in an impressed area, 

 marked by deeply cut line; concentric 

 laminae forming spines near edge of poste- 

 rior area; tinted with color but not in 

 patterns; inner edge smooth; pallial sinus 

 tongue-shaped; hinge as in Pltar. 



HYSTEROCONCHA DIONE Linn§. This very 

 striking shell was the species selected by 

 Llnne upon which he based the technical 

 terms used in describing the genus Venus. 

 It was widely known, years ago, as the 

 "true Venus shell." There are two rows of 

 spines, one more prominent than the other. 

 Length 35 mm. Color pinkish violet. 



PI. 18, Fig. 4 



Texas and Vi/est Indies 



GENUS ANTIGONA Schumacher 1817; 

 Cytherea Bolten 1798, not Fabriclus 1794 



Shell strong and rotund, convex, 

 sculpture strong, ligament deep-seated; 

 left anterior lateral tooth the larger and 

 with socket in right valve opposite; pos- 

 terior right cardinal tooth broad and bifid; 

 pallial sinus small and triangular. 



ANTIGONA LISTERI Gray. Shell oblong, hinge 

 line nearly straight, concentric and radial 

 sculpture strong. Length 2-3 inches. 



This well-known Vt/est Indian shell 

 occurs at intervals in Lake Worth, Florida. 

 It is more frequent In Biscayne Bay and 

 still more so among the lower Keys. 



PI. 21, Fig. 11 



Lake Worth, Florida to West Indies; 



Marco, west Florida 



GENUS CYCLINELLA Dall 1902 



Three cardinal teeth in each valve; 

 limule circumscribed; siphons of animal sep- 

 arated. 



CYCLINELLA TENUIS Recluz. A rather deli- 

 cate, white, shell which somewhat resem- 

 bles Dosinia. It lives in sand at a depth 



of about 2 fathoms. Height 1 inch. 

 PI. 21, Fig. 1 



Cedar Keys, west Florida south 

 through the West Indies to Brazil 



GENUS CHIONE Megerle von Muhlfeld 1811 



Attractive, trigonal, solid shells; 

 three cardinal teeth in each valve (except 

 in a few degenerate forms); valve margins 

 scalloped; sinus always triangular; liga- 

 ment inset but always visible outside; 

 sculptiire variable, often with leaf-like 

 processes. 



The concentric sculptixre, rather 

 than the radial, is usually dominant. 



CHIONE CANCELLATA Linne. Shell almost 

 heart-shaped, gray, triangular, thick, 

 crenulated, varices at regular intervals; 

 dorsal area excavated and flat; generally 

 with a patch of purple inside. Length 1 

 inch. 



A very common and variable species 

 which lives in shallow water. It is abun- 

 dant in Lake Worth, Florida. Larger exam- 

 ples live near Beaufort, North Carolina. 



PI. 21, Fig. 5 



PI. 7, Fig. 5 



Cape Hatteras, North Carolina to 



Brazil 



CHIONE INTAPURPUREA Conrad. Shell moder- 

 ately pointed at posterior end; umbones 

 small and low; luniile prominent and often 

 dark brown; concentric ribs strong, radial 

 lines weaker; margin of shell toothed; ex- 

 terior variously marked with brown; umbones, 

 margin and a portion of interior purplish. 

 Length 35 mm. 



PI. 54, Fig. 2 



PI. 57, Fig. 8 



Cape Hatteras, North Carolina to 



Florida Keys and mainland to Texas; 



Honduras 



CHIONE MAZYCKII Dall. The quadrate form 

 and bright rose colored interior are the 

 most prominent characters of this pretty • 

 species. Length 12 mm. It lives in 15-1S7 

 fathoms. 



PI. 20, Fig. 6 



Cape Hatteras, North Carolina to 



Brazil 



CHIONE PUBERA Valenciennes. A fine large 



