MOLLUSOA OF PORTO RTOO. 
475 
Psammosolen sanctae-marthas d’Orbigny. 
Solcn sancUe-marthx Chemnitz, Conch. Cab., xi, p. 203, pi. oxevm, fig. 3938,1795; d’ Orbigny, Moll. Cnbana, n, p. 232, pi. xxv, 
figs. 31,32, 1845. 
Shell long-quadrate, gaping widely at each end, the valves only touching at the hinge and central 
base; beaks low; ligament extending in front of and behind the beaks, inflated into a rounded ridge 
immediately behind them and then suddenly flattened; growth lines rather rude; all the shell except 
its extreme anterior portion is obliquely sculptured, the ridges dividing on the low, rounded posterior 
ridge; epidermis yellowish or horn-colored, wearing off except around the margin of the shell; left 
valve with one high, compressed cardinal just behind the beak; right valve with a similar cardinal 
under the beak; pallial sinus wide and deep. Color whitish. 
Length, 37; height, 20; diameter, 12 mm. 
Mayaguez, one young broken valve. 
There are sometimes vestiges of a second cardinal in each valve. 
Genus SOLEN Linnaeus, 1758. 
Shell very long, subeylindrical; the dorsal and ventral edges parallel, inequilateral, straight or 
nearly so; surface more or less sculptured with the growth lines; divided by an oblique line running 
from the beaks to the post base; extremities widely gaping; hinge with a single cardinal in each valve; 
ligament elongated, external; anterior muscle impression elongated, parallel with the dorsal border, 
pallial sinufe short. 
Section SOLENA Morch, 1853. 
Solen obliquus Spengler. 
Solen obliquus Spengler, Skrift. Nat. Selsk., in, p. 104, 1794. 
Solen ambiguus Sowerby, Conch. Icon., xix, pi. v, fig. 21, 1874. 
Shell rather solid, subeylindrical, straight, the beaks placed at one-sixth of the length of the shell 
from the anterior end; anterior end. obliquely truncated, longer below; the shell is decidedly thickened 
at this part and appears as if cutoff; posterior end nearly squarely truncate, thin; epidermis rudely 
wrinkled, growing beyond the shell, ashy or brownish ; there is one high, straight tooth in each valve 
under the beaks, that of the right valve in front of the one in the left; anterior muscle scars elongate, 
placed under the beaks; posterior scars semilunar, the dorsal edge straight, the wide pallial line 
connecting with the center of its base and forming a -<; in the fork of this is the small pallial sinus. 
Length, 110; height, 22; diameter, 14 mm. 
Cabo Rojo light, Porto Rico, one specimen. 
Superfamily TELLINACEA. 
Family PSAMMOBIDtE. 
Genus HETERODONAX Morch, 1852. 
Heterodonax bimaculatus Linnaeus. 
Tellina bimaculata Li mucus, Syst. Nat., eel. x, p. 577, 3758; Sowerby, Conch. Icon., xvn, 1866, pi. xviii, fig. 94 ci-c. 
San Juan, Porto Rico (Gundlaeh). 
Genus TAGELUS Gray, 1847. 
Tagelus gibbus Spengler. 
Solen gibbus Spengler, Skrift. Nat. Selsk., in, p. 104, 1794. 
Solecurtus caribseus Sowerby, Conch. Icon., xix, pi. iv, fig. 21,1,874. 
Mayaguez, Porto Rico (Gundlaeh). 
Genus ASAPHIS Modeer, 1793. 
Shell transverse, somewhat rhomboid, subequi lateral, beaks rather prominent; hinge having two 
cardinals in each valve, the anterior in the left and the posterior in the right bifid; ligament thick; 
adductor scars near the dorsal edge; pallial sinus deep, rounded. 
