604 TRANS. OF THE ACAD. OF SCIENCE. 
C. Tuvomey!, n. sp. 
make a sufficiently minute comparison. If the two shells 
should prove to be identical, the name above given must still 
be adopted, since the specific name candata was applied by 
Nilson to a European shell of this genus, some years before 
the description of Tuomey was published. 
Form. and Locality.—Occurs in the Septaria of the a, 
er Cretaceous Group, in Grayson County, four and a =" 
miles north of Sherman. Collected by Dr. G. G. Shumard. 
GENUS PACHYMYA. 
P, AUSTINENSIS, Nn. Sp. 
Shell very large, length more than double the width, = 
less than double the thickness; greatest width near the * 
ter, where the shell is very gibbous; subangulated soe ra 
from the posterior side of the beak to the anal extremity al 
: inal 
and very gently convex posteriorly ; beaks ie x ie 
flattened, incurved, approximate; surface marked w} 
h 
Length, 6.30 inches; width, 2.30; thickness, 3.64. 1 with, 
This shell is very nearly related to, if not identica’ 
P. gigas of Sowerby (Min. Conch., Vol. 6, p- 1; 1, rceive 
The only essential points of difference that I can baci the 
are, that in the foreign shell the beaks are situated nearer 
ae ue 
anterior extremity, and the sides do not exhibit the obliq 
