CRASSATELLIDZA. 225 
pit is seen posterior to them in both valves, and judging from 
the general resemblance of the shell to Crassatella, it is probably 
destined to receive a cartilage. 
Pronok, Agassiz, 1843. 
Syn.—Venulites, Schloth. 
Distr.—Liassic; Europe. P. triangularis, Schloth. 
Shell subtrigonal, like an Astarte or Cytherea, with slight 
concentric striation on the surface; hinge of the right valve 
with two cardinal teeth, the anterior one extending somewhat 
below and forming the margin of an elongated pit, above which 
there is a small sublunular tooth; a small oblique cartilage-pit 
is situated just behind the beak and a large remote posterior 
lateral tooth is also present; fulcrum strongly thickened. The 
hinge of the left valve must possess two cardinal and one sub- 
lunular and one posterior double lateral teeth. If Quenstedt’s 
figure and description of the hinge of P. triangularis, Schloth., 
is correct, this would be the oldest form of Crassatellidz, though, 
as that author remarks, the hinge-teeth of the right valve very 
much resemble those of a Cyprina; and should it be proved 
that the small pit is only an accidental depression in which a 
part of the external ligament is situated, the generic name would 
have to be cancelled, and the species referred to Cyprina, with 
which the shell perfectly agrees in form. 
CRASSATELLINA, Meek, 1871. 
Syn.—Etea, Conrad, 1873. 
Distr.—C. oblonga, Meek (cxxi, 7-9). Cret.; U.S. 
Shell transversely trapezoidal, equivalve, inequilateral, with 
free margins closed and smooth within ; hinge with two cardinal 
teeth, and one elongated anterior and one posterior lateral tooth 
in each valve ; anterior cardinal tooth of the left valve trigonal, 
and deeply emarginate below ; posterior very much compressed, 
oblique, and somewhat elongated; cardinal teeth of right valve 
diverging, with a triangular pit between for the reception of the 
larger triangular tooth of the other valve; anterior one small, 
oblique. and connected at its upper end with the posterior 
extremity of the anterior lateral; posterior larger, oblique, 
longitudinally furrowed, and perhaps emarginated below, while 
just behind and above it there is a narrow oblique slit or pit, for 
the reception of the thin anterior cardinal of the other valve; 
lateral teeth elongated parallel to the cardinal margins; the 
anterior one of the right valve, and the posterior of the left, 
apparently continued so as to connect with the upper ends of 
the cardinal teeth ; ligament external; pallial line simple. 
ERIpHy.a, Gabb, 1864. 
Syn.—Dozyia, Bosquet, 1868. Gouldia, C. B. Ad. (in part). 
