Page:American Seashells (1954).djvu/511

Rh ¼ to ½ 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, Transmella simpsoni, ½ inch; c, T. conradina Dall, ½ 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

¼ 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.