598 TRANS. OF THE ACAD. OF SCIENCE. 
surface smooth, or marked with fine lines of growth. 
Length, 0.66; width, 0.53; height of body volution, 0.48. 
Locality.—V ery abundant near the base of the Upper Cre- 
taceous series, in the Caprotina Limestone, Parker County, 
,near Brazos River. B. F. Shumard and W. P. Riddell, col- 
lectors. 
GENUS NERITOPSIS. 
N. BIANGULATUS, N. sp. 
Shell depressed, width greater than the height; spire short, 
obtuse at apex (in cast), forming about one-fifth of the total 
height of the shell; volutions 83-3} angulated above, upper 
surface narrow, flat, declining very gradually from angle 0 
eriphery to suture ; last volution very large, transverse diam- 
eter greater than the height, periphery convex, angulated be- 
low, but less sharply than above; surface of cast exhibiting 
obscure, coarse striw, which are preserved only on the side of 
the body volution, where they pass obliquely downwards and 
backwards from the superior to the inferior angle. 
Height, 1.10 in.; width, 1.42. 
The few examples of this species we have seen are scone 
and occur with Inoceramus problematicus and Hamites Fremonti 
near the base of the Upper Cretaceous Limestone. 
Locality —Alexander’s Bend, Grayson County. 
ACEPHALA. 
GENUS VENUS. 
V. SUBLAMELLOSUS, D. Sp. 
ase semiovate; beaks nearly central, moderately “s se 
closely incurved, approximate; lunule rather large we i. 
late, not deeply impressed, but with margins distinct iota 
fined; ligament area narrow lanceolate, pallial sinus ie i 
large, extremity rather bluntly rounded; surface ma 
with prominent, sharp, sublamellose, concentric stri®. aa 
Length, 0.57; width, 0.49; thickness, 0.26. This nf d 
little species, and quite distinct from any hitherto ene 
species from American strata. ‘ f which 
The collection contains but two specimens, neither 0 
