132 SOLENIDA. 
Shell subeylindrical, transversely elongated, rounded and 
gaping at the extremities; beaks anterior to the centre; ante- 
rior muscular impression elongated, subtrigonal; pallial impres- 
sion with a small sinus. 
Siphons shortly produced and separate; foot large, abruptly 
truncate. Inhabits the muddy estuaries of rivers. 
CERATISOLEN, Forbes. 
Syn.—Pharus, Leach, teste Gray, 1840.  Polia, d’Orbigny. 
Solecurtoides, Desm. 
Disir.—2 sp. Britain, Mediterranean, Senegal, Red Sea, 
Singapore. Fossil, 3 sp. Miocene; Italy. C. legumen, Linn. 
(evi, 12). 
Shell narrow, subequilateral, anterior adductor impressions 
elongated, a second pedal scar near the pallial sinus. 
Animal with a long, truncated foot; siphons separate, diver- 
ging, fringed. 
LEGUMENATA, Conrad, 1858. 
Distr.—L. elliptica, Cony. (evi, 14). Cret.; U.S. 
Valves very inequilateral; hinge with two very slender teeth 
in the right valve under the beak, and one posterior, very 
oblique, prominent, lamelliform tooth. This group was proposed 
for a cretaceous species; the form of the teeth and their posi- 
tion agrees with Novaculina, but the posterior tooth is not lamel- 
liform in this genus. A character of further importance is 
stated to be the shortness of the posterior part of the shell, 
which is not seen in any of the European or Indian cretaceous 
species ; it does, however, occur in some of the recent American 
species of Tagelus, from which Legumenaia would differ by its 
dentition, but externally it would seem impossible to distinguish 
between both of them. 
LeEprosoLen, Conrad, 1867. 
Distr.—L. biplicata, Cony. Cretaceous; U.S. 
Elongated, thin in substance, straight, with the dorsa! and 
ventral margins parallel; plicated anteriorly, open at both ends; 
beaks not nearly terminal; hinge of the right valve with one 
direct tooth, convex anteriorly, truncated behind; an internal, 
rounded, direct rib commences under the cardinal margin, grad- 
ually becomes less prominent, and disappears towards the 
ventral margin. 
If the existence of a single tooth in the right valve can be 
considered as a permanent, distinctive character, the separation 
from Siliqua would have good grounds. The tooth is said to 
be broadest at the hinge-plate, and tapers to a very acute edge, 
which is expanded in the direction of the shell’s diameter. This 
peculiarity in the form of the principal or cardinal tooth is often 
