download pdf

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;
Transennella conradina Dall
c, T. conradina Dall, % inch.
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.