LEA ON SOME NEW FOSSIL MOLLUSCS, &c. 
27 
his Index Palaeontologicus, gives a long list of this genus, nearly 200, two species of 
which were observed by Verneuil, in the Coal Formation, M. Teplopi and M. Pallesi. 
In the specimen from the vicinity of Wilkesbarre, formerly known as Wyoming, 
there are at least two distinct species, one broad and rather large, and the other small 
and much more transverse in proportion. PI. 20, fig. 1 a, represents the larger, and 
fig. 2 the smaller. I propose to call the first Modiola Wyomingensis , and the second 
M. minor. There are also several species which seem to me to be more analogous 
to Posidonia, than to any genus I am acquainted with. I propose to put these 
provisionally in Posidonia, and to name them P. clathrata, P. perstriala and P. 
distans. Several small fish scales are distributed over the surface, on both sides of 
the laminated specimen. These probably belong to the genus Palceoniscus, and to it 
I shall refer them, under the name of P. Leidyiana, (pi. 20, fig. 4 and 5,) in the hope 
that perfect specimens may be obtained hereafter. 
Modiola Wyomingensis. Plate 20, fig. 1 a. 
Testa Itevi triangulari, inferne compresso-alata; umbonibus elevatis, acute angulatis. 
Remarks. —This is a broad flat species, very different from the minor, which is on 
the same specimen. There are parts of four distinct specimens on this small piece of 
slate, which is represented of the natural size. 
Modiola minor. Plate 20, fig. 2. 
Testa infernb 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 perfect, and very distinctly marked. 
Posidonia ? clathrata. Plate 20, fig. 1 b. 
Testa complanata, clathrata, rotuudato-obliqua, striata; striis decussatis. 
Remarks. —There are two specimens of this species lying together on the stone, 
both of which are imperfect. One is more oblique than the other, and they may 
eventually prove to be distinct species. 
Posidonia ? perstriata. Plate 20, fig. 3 a. 
There is too small a portion of this species remaining on the surface of the specimen, 
to characterize it by a proper diagnosis. Perhaps a third of the valve only remains, 
but this is perfect, and beautifully and transversely striate—the strise being parallel. 
Posidonia ? distans. Plate 20, fig. 3 b. 
Like the above, there was but a small portion of a valve found. It has longitudinal 
striae, somewhat like perstriata, but the striae are more distinct and distant, amounting 
almost to ribs. 
