142 AMERICAN MARINE CONCHOLOGY. 
Family SOLENID&. 
Animal with a very large, more or less cylindrical foot ; siphons 
short and united (in the typical species, with long shells) or longer 
and partly separate in the shorter and more compressed genera; 
gills narrow, prolonged into the branchial siphons. 
Usually living buried vertically in the sand. 
Synopsis of Genera. 
Shell very long, nearly straight, ends gaping, hinge terminal. One pri- 
mary tooth in each valve. Pallial impression with a short square sinus. 
SOLEN. 
Shell very long, gaping and rounded at each end, beaks nearly terminal. 
Hinge with two teeth in one valve, and three in the other. Pallial line 
with a small, truncate sinus. ENsIs. 
Shell transversely oblong, curved, rounded and gaping at the ends with a 
rugose epidermis. Beaks sub-central, hinge teeth 2, 3. Sinus of pallial 
impression very deep, extending beyond the umbo. SILIQUARIA. 
Shell transversely oblong, epidermis polished, ends rounded and gaping. 
Hinge anterior to the middle, with three teeth ineach valve. Pallial line 
with a short, rounded sinus. SILIQUA. 
Genus SOLEN, Linnzus. 
Syst. Nat., edit. x. 672. 1758. 
1. S. viripis, Say. Figs. 329, 330. 
Journ. Philad. Acad., ii. 816. 1822. 
Shell transversely oblong, compressed. Hinge margin nearly 
straight ; basal margin curved ; posterior end obliquely truncated, 
a little reflected and rounded near the base ; anterior end rounded. 
Smooth, with very slight concentric growth lines. Epidermis pale 
green. 
Length 2 inches, height .4 inch. 
New Jersey Coast, southwards. 
Genus ENSIS, Schumacher. 
Essai, Nov. Gen. 143. 1817. 
Solen (part) Auct. 
1. E. AMERICANUS, Gould. Fig. 331. 
Invert. Mass., edit. ii. 42. 1870. 
Shell elongated; cylindrical, slightly curved, ends truncately 
rounded. Epidermis glossy, with a long triangular space marked 
by concentric growth lines, above and below covered with lines 
