NO. 1614. NHW AND OLD CARBONIFEROUS FOSSILS—GIRTY. 291 
broadly below, where it is almost marginal, descending abruptly on 
the anterior side and very gradually behind. Beak nearly terminal, 
leaving, for the genus, a rather large lobe in front. Anterior outline 
sinuous, posterior outline gently convex. Anterior-superior angle 
rounded, posterior-superior angle obtuse. Inferior angle strongly 
rounded. Surface marked by sublamellose growth lines. 
Several other specimens of various sizes and degrees of fragmen- 
tariness occur on the same slab. One of these, an imperfect mold of 
the exterior, seems to have been the original of Lea’s J/odiola minor. 
On the slab this specimen occurs near the posterior-superior angle of 
M. wyomingensis, but Lea shows it not in his figure of the whole slab 
but in a separate figure (fig. 2). Originally it bore a very close 
resemblance to Lea’s illustration, but by removing part of the rock its 
appearance has been changed and its general resemblance of J/. wyo- 
mingensis so enhanced as to leave scarcely a doubt that it belongs to 
the same species. : 
M. wyomingensis proves to have had a very extensive distribution, 
since what appears to have been the same species has been identified 
in Colorado. Lea’s description of Jfodiola minor, which is here re- 
garded as a synonym of I/yalina wyomingensis, is as follows: 
“Testa inferne striata, elliptica, subplanulata; antico latere 
rotundato. 
_* Remarks——A single specimen only was found of this species, and 
the umbones are obliterated. The lower part, as represented, is per- 
fect, and very distinctly marked.” 
Locality and horizon.—Pennsylvania; Wilkesbarre, Pennsylvania. 
Ty pe-speciomens.—Cat. Nos. 33899 and 33900, U.S.N.M. 
MODIOLA MINOR Lea. 
This species is based upon an external mold of an imperfect valve. 
The type-specimen occurs in association with I/yalina wyomingensis, 
which appears to have been abundant, and as it agrees with that 
species in such characters as can be determined, it will be reasonably 
safe, as well as advantageous, to regard it as identical with Jf. wyo- 
mingensis and the name as a synonym. 
DELTOPECTEN CLATHRATUS Lea. 
Plate SGX. figs le 
1853. Posidonia? clathrata Lea, Acad. Nat. Sci. Philadelphia, Jour., (2), 
JUL, jO> AAG, jOll, SOx, tale, Ita, « 
The characters of this species are much in doubt. The types con- 
sist of two specimens lying close together and possibly even represent- 
ing different valves of the same individual. One, which appears to 
be smaller but may only be imperfect, is almost certainly a represen- 
tative of the genus Deltopecten. It has a broad, oblique cardinal 
area, with a large triangular cartilage pit beneath the beak. The 
