LEA ON SOME NEW FOSSIL MOLLUSCS, &c. 205 



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. perstriaia and P. 

 distans. Several small fish scales are distributed over the surface, on both sides of 

 the laminated specimen. 1 hese 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 Isevi triangulari, infern^ 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 infern^ 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 1 clathrata. Plate 20, fig. 1 b. 



Testa complanata, clathrata, rotundato 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 striae 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 



strife, somewhat like perstriaia, but the striae are more distinct and distant, amounting 



almost to ribs. 



52 



