Page:American Seashells (1954).djvu/530

432 /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 constrict a 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 Figure 88d Alaska to Lower California. 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 Figure 88c Vancouver Island to the Gulf of California. 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. 1