MOLLUSC A OF PORTO RIOO. 
481 
Tellina vitrea d’Orbigny. 
Tellina vitrec td'Orbigny, Moll. Cubana, ir, p. 253, pi. xxvi, figs. 4, 5, 1845. 
Shell subsolid, nearly twice as long as high, compressed, a little narrowed and rounded in front, 
truncate above behind; beaks somewhat back of the center; posterior ridge low, with a second faint 
ridge above it near the edge of the shell; the hinder part of the shell subbiangulate below; surface 
with low tine ribs; in some specimens these are quite distinct, in others they are scarcely more than 
growth lines; the whole is polished and shining. Color pink, often tinted with yellow, deep pink 
within; left valve with two divergent cardinals, that in front bifid, and two faint laterals; right valve 
with two cardinals, the hinder bifid, and two well-developed laterals; pallial line very deep. 
Length, 33; height, 18; diameter, 6 mm. 
Mayaguez, one right valve; Boqueron Bay, Porto Rico, one specimen. 
Genus MACOMA Leach, 1819. 
Valves with a marked posterior flexure, usually subtrigonal, and with a smooth or concentrically 
striate surface; hinge without lateral teeth; the siphons naked; the pallial sinus deep and usually 
coalescent with the pallial line below. Type, M. tenera Leach = Tellina calcarea Gmelin. 
Macoma constricta Bruguiere. 
Solen conslrictus Bruguiere, Mem. Soc. cl’ hist. Nat. Paris, i, p. 126, 1799. 
Tellina cayennensis Hanley, Thes. Conch., p. 312, pi. lxii, fig. 190, 1846. 
Quebradillas, Porto Rico (Gundlach). 
Macoma tenta Say, var. souleyetiana Recluz. 
Tellina souleyetiana Recluz, Journ. de Conchyl., in, p. 253, pi. x, figs. 5, 5', 1852. 
Shell thin, rather elongated, with dorsal and ventral lines parallel, rounded in front, truncate 
above behind, the posterior end somewhat drawn out, having two low posterior ridges ending in a 
truncated point a little above the base of the shell; the surface is nearly smooth and, though scarcely 
shining, it is faintly iridescent; around the outer part of the shell there is a fuscous epidermis; left 
valve with two cardinals, the anterior the larger; right valve with two cardinals, the posterior very 
small; pallial sinus rising high under the beaks, as in M. tag cl [for mis. Color generally white. 
Length, 18; height, 10; diameter, 6 mm. Mayaguez, Porto Rico, many shells. 
Resembles a small M. brevifrons Say, but the posterior end is more strongly flexed than in tha 
species and considerably more drawn out. The hinder end is narrow and distinctly truncated, while 
in M. brevifrons it is wider and irregularly rounded. It is probably a southern variety of M. tenta Say. 
Macoma pseudomera, n. sp. Plate 56, fig. 5. 
Shell small, rather thin, solid, white, inequilateral, subequivalve; surface smooth except for 
fine, close, incremental lines and faint radial striations, but not polished; beaks not prominent; 
valves moderately convex, form as figured; interior white, polished, usually with well-defined scars, 
frequently dotted over the middle of the disk with a multitude of microscopic punctations; pallial 
sinus subcircular, almost wholly free from the pallial line and extending but little behind the middle 
of the shell; ligament short; hinge normal. 
Length, 16; height, 12; diameter, 6 mm. 
Mayaguez Harbor, Porto Rico, at station 6062, in 30 fathoms, sand, rather abundant; San Juan 
Harbor at station 6053, in fathoms, sand. Also at Bermuda and Jamaica (Vendryes). 
This species bears a close external resemblance to Angulusmera Say, but has no lateral teeth and 
the form of the pallial sinus is entirely different. The periostracum is hardly noticeable, but is pale 
yellowish and papery, sometimes pubescent near the margin. 
Subgenus Psammacoma Dali, 1900. 
Macoma brevifrons Say. Plate 55, figs. 3, 12, 13. 
Tellina brevifrons Say, Am, Conch,, vn, p.227, pi. 64, fig. 7 (bad), 1834. 
Shell oblong, subsolid, somewhat rhomboidal; the dorsal and ventral lines nearly parallel, 
subinflated; posterior slope truncated; the posterior end turned to the right, irregularly rounded and 
gaping; umbonal region smooth, whitish, somewhat shining and iridescent, the later growth covered 
with a cloth-like cinereous epidermis; left valve with a bifid cardinal under the beak and a small one 
F. C. B. 1900—31 
