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432 Afnerican Seashelh
/4 to % inch in length, fragile, elongate, white in color with a delicate
iridescence on the smooth exterior. Posterior and narrower end slightly
twisted to the left. This small, tellin-like species is very common in shallow
water in sand. M. soiileyetiana Recluz is the same.
Macoma limiila Dall is very similar in size and shape, although somewhat
more elongate, and is distinguished by the finely granular external surface
of the valves. Commonly dredged from North Carolina to Florida.
Macoma constricta Bruguiere Constricted Macoma
Florida to Texas and the West Indies.
1 to 2/4 inches in length, moderately elongate. The posterior end is
twisted to the right and is narrowed to a blunt point. Color all white with
concentric growth lines stained by the gray periostracum. Common just off-
shore.
Macoma nasuta Conrad Bent-nose Macoma
Alaska to Lower California.
Figure 88d
2 to 3% inches in length, elongate, rather compressed and strongly
twisted to the right at its posterior end. Beaks slightly nearer the anterior
end. Can be distinguished from other Pacific Coast species by the paUial
sinus in the Jejt valve which reaches the anterior muscle scar. One of the
commonest species on the west coast and lives about 6 inches below the
surface of the mud in quiet waters from shore to 25 fathoms.
Macoma secta Conrad White Sand Macoma
Vancouver Island to the Gulf of California.
Figure 88c
2 to 4 inches in length. This is the largest Macoma in America and is
characterized by the almost flat left valve, rather well-inflated right valve,
and by the wide and relatively short ligament which is sunk partially into
the shell. There is a large, oblique, rib-like extension just behind the hinge
inside each valve. Color cream to white. Common in bays and beaches from
shore to 25 fathoms. A small form occurs in protected waters in bays in its
more southerly range.
Students of the Pacific Coast fauna consider M. indentata Carpenter
(same range) as a distinct species in which the shell is 1% inches in length,
a little more elongate, with a more pointed posterior end, and with a slight
indentation on the posterior ventral margin. It may possibly be a form of
young secta. M. teniiirostris Dall is even more elongate and may also be a
form.
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