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458 Ajnerican Seashells
of dark-brown periostracum. Concentric sculpture of distinct ridges. Color
yellowish to brownish white. Uncommon in shallow water.
Corbula barrattiajia C. B. Adams
North Carolina to both sides of Florida and the West Indies
Barratt's Corbula
Figure 93a
^ inch in length, moderately compressed, rostrate at the posterior end,
with poorly developed or without concentric ridges in the beak area. Right
valve slightly larger than the left. The posterior end of the rostrum in the
right valve projects far beyond that of the left valve. Color variable: white,
pink, mauve, yellow, orange or reddish. Uncommon in shallow water to
50 fathoms.
Figure 93. Corbula clams, a, Corbula barrattiana C. B. Adams, Y^ inch (Atlantic
Coast); b, Corbula swijtiana C. B. Adams, ^ inch (Atlantic Coast). Three views
of each
Corbula sioipiana C. B. Adams
Massachusetts to east Florida and the West Indies.
Swift's Corbula
Figure 93b
/4 inch in length, oblong, moderately obese; right valve larger, more
obese and overlapping the left valve at the ventral posterior region. Posterior
slope in the right valve bounded by 2 radial ridges, one of which is close
to the margin of the valve. The left valve has only i ridge. Shell thick, with
the posterior muscle scar on a slightly raised platform. External sculpture
the same on each valve, consisting of irregular, concentric ridges. Color