VENERIDAE 



413 



^ to % inch in length, glossy, rounded trigonal in shape, smooth except 

 for fine growth lines. Inner margins of valves creased with microscopic 

 oblique threads. Exterior cream with 2 or 3 wide, radial bands of weak 

 brown. Interior commonly flushed with purple. Pallial sinus long. Fairly 

 common in shallow water. 



Figure 83. Atlantic Transennella Clams, a and b, Trfl725e72wd/a jfimp^cwi, % inch; 



c, T. conradina Dall, % inch. 



Transennella conradina Dall 



South half of Florida and the Bahamas. 



Conrad's Transennella 



Figure 83c 



Shell very similar to that of stimpsoni, but differing in being pointed 

 posteriorly, hence more elongate, and more variable in color. Zigzag brown 

 lines present in some, others are solid cream or solid brownish. Exterior 

 with fine, raised, concentric lines. Pallial sinus short. Common in shallow 



water. 



Transennella tantilla Gould 



Alaska to Lower California. 



Tantilla Transennella 



% inch in length, ovate, angle at beaks about 90 degrees, smooth except 

 for weak, concentric lines of growth. Immediately recognized under the 

 hand lens by the tiny grooves running on the inside of the shell margins. 

 Exterior cream with the posterior end stained bluish. Interior white with a 

 wide, radial band of purple-brown at the posterior end. Dredged in large 

 numbers off California and at times found washed ashore. 



"Pitarid'' Group 



Beaks generally nearer the anterior end; cardinal teeth not tending to 

 radiate; anterior laterals well-developed. 



