580 



MOLLUSCA 



Fig. 911 — Lampsilis radiata 

 (Gould). 



L. ventricosa (Barnes). Pocket-book clam. Shell swollen, ovate, 

 thick and heavy, rounded before and behind, 15 cm. long, 9 cm. high and 



6 cm. wide: valleys of Mississippi and St. 

 Lawrence, in large streams and lakes; com- 

 mon; used in button-making. 



L. gracilis (Barnes). Shell elliptical, 

 compressed, round in front, rounded and 

 very broad behind, 12 cm. long, 7 cm. high, 

 4 cm. wide; color yellow with green rays 

 extending from the umbo; cardinals weak, 

 but 1 in each valve: Mississippi and St. Lawrence valleys; Hudson River; 

 on muddy bottoms. 



L. recta (Lamarck). Black sand shell (Fig. 912, A). Shell elon- 

 gate, compressed, heavy, rounded in front and triangular behind, 11 cm. 

 long, 5 cm. high, and 3 cm. wide, black in color; 2 cardinals in each 

 valve: Mississippi and St. Lawrence valleys, in large lakes and rivers; 

 used in button-making. 



L. anodontoides (Lea). Yellow back. Shell elongate, swollen, tri- 

 angular behind, 8 cm. long, 35 mm. high, 27 mm. wide, bright yellowish- 

 brown in color; 2 cardinals in each valve: valley of the Mississippi and 

 of the Gulf of Mexico; used in button-making. 



Fig. 912 



Fig. 913 



Fig. 912— A, Lampsilis recta; B. L. luteola; C, L. iris (Baker). Fig. 913 — 

 Strophitus edentulus (Baker). 



L. luteola (Lamarck) (Fig. 912, B). Shell elliptical, inflated, 

 rounded in front and oval behind, 11 cm. long, 6 cm. high, and 48 mm. 

 wide; color light or dark green; 2 cardinals in each valve: Mississippi 

 and St. Lawrence valleys, in lakes and rivers; common. 



L. iris (Lea) (Fig. 912, C). Shell small, elliptical, compressed, 57 

 mm. long, 3 cm. high, 2 cm. wide; color yellowish, with numerous wide, 

 interrupted, green, radial rays; 2 cardinals in each valve: New York to 

 Illinois, south to Texas; common. 



L. ligamentina (Lamarck). Mucket. Shell elliptical, thick, and 

 heavy, 10 cm. long, 6 cm. high, and 35 mm. wide, yellowish or greenish 

 in color, with dark radiating rays ; 2 cardinals in each valve : Mississippi 

 and St. Lawrence valleys; used in button-making. 



