1881.] NATURAL SCIENCES OF PHILADELPHIA. 417 



I have been unable to discover the description of this species. 

 A specimen with this name in the Academy's collection, and 

 marked in Conrad's handwriting, scarcely admits of positive 

 specific determination. It has been considerably eroded, and 

 appears as though it may have been either closely related to, or 

 identical with P. calvatus (Mort.). 



P. Deshayesii Lea. Ala. 



" Contributions to Geology," p. 87. 

 P. Lyelli Lea. "Contr. to Geol.," p. 88 (young). 



Both of Lea's figured specimens are in the Academj^'s collection, 

 and show beyond doubt that the}' belong to one and the same 

 species, what there is of P. Lyelli corresponding precisely to the 

 earlier formed portion of P. Deshayesii. This last must be care- 

 fully distinguished from the P. Deshayesii of Nj'st (" Coqu. eP 

 Polyp. Foss.,^^ p, 288), which was founded on the erroneous; 

 supposition that Lea's species was only a variety of P. opercic- 

 laris, Lam. ; a new specific name should therefore be given to the 

 Belgian Pecten. 



P. elixatus Conr. ( Janira), Jacksonian ? S. Car. 



Proc. A. N. S., ii, p. 174. 



P. Knieskerni Conr. N. J. 



A. J. Conchol., V, p. 40 (described from a cast). 



P. membranosus Mort. Jachsonian. Ala. ; S> Car..; N. Car» 



Syn. Org. Kem., p. 59. 



P. nuperus Conr. Jacksonian. Miss. 



Proc. A. N. S., vii, p. 259. 



P. scintillatiis Conr. (Camptonectes). Miss. 



A. J. Conchol., 1, p. 140, as Eburneopecten , 



Oligocene. 

 p. anatipes Mort. Ala. 



Syn. Org. Rem., p. 58. 



P. perplai us Mort. Ala. ; Miss. 



Syn. Org. Rem., p. 58. 

 P. Spillmani Gabb. J. A.N. S., 2d series,, iv, p. 402. 



The original specimen of P. Spillmani in the Academy's collec- 

 tion agrees thoroughly with P. perplanuSy and is marked as its 

 equivalent in Gabb's handwriting.. 



P. Poulsoni Mort. (Janira). Ala.; Miss. 



Syn. Org. Rem., p. 59. 



