1879.] NATURAL SCIENCES OF PHILADELPHIA. 219 



culatum, Lam.; Bulimus (Niso) terebellatus, Lam.; Sigaretus 

 canaliculatus, Sow.; Calyptraea (Trochita) trochiformis,'Lam.; 

 Pyrula tricarinata, Lam.; Avicula trigona, Lam.; Cytherea ery- 

 cinoides, Lam.; C. sube?ycinoides, Desh.; Corbis lameuosa, Lam.; 

 and Fistulana elongata, Desh., most of which on examination 

 prove to be as well American as European forms. In the Ap- 

 pendix to Morton's Synopsis ("Synopsis of the Organic Remains 

 of the Cretaceous Group," 1834) only six European species are 

 recognized as occurring in the American formation : Solarium 

 canaliculatum, Lam.; S. patulum, Lam.; Bulimus terebellatus, 

 Lam.; Gardita planicosta, Lam.; Corbis lameliosa, Lam.; and 

 Fistulana elongata, Desh. In the list published by Conrad in 1846 

 (Airier. Journ. Science, 2d ser. vol. i. p. 219), of the preceding 

 enumerations only two species are retained as being " analogous" 

 to transatlantic forms, Cytherea Mortoni, Con ( Cytherea ery- 

 cinoides,Ija,m.; and C. suberycinoides, Desh.) and A vicula limula, 

 Con. (A. trigona, Lam.), but in addition we have five new ones 

 catalogued: Cardita Blandingi, Con. (C. acuticosta, Lam.) ; G. 

 rotunda, Lea. (C. asperula, Desh.) ; Cardium Nicolleti, Con. (C. 

 semigranosum [ granulatum'], Sow.) ; Turritella Mortoni, Con. 

 (=?) ; and RosteUama laqueata, Con. (R. Jissurella, Lam.). 

 Finally, all species considered identical prior to 1866 are rejected 

 as such with one exception (Cardita planicosta) in the Smithso- 

 nian List. The reasons for so doing, which, in the majorit}' of 

 cases, I believe, are not stated, appear to me incomprehensible. 



In the introduction to his " Contributions to Geology," 1833, p. 

 19, Mr. Lea states that he is "not perfectly satisfied that a single 

 species is strictly analogous to those from the Eocene Period of 

 Europe ", but in a note (pp. 207, 208) makes the fol- 

 lowing comparisons : Pasithea umbilicata, Lea, with Bulimus lere- 

 bellatus, Lam. ; Venericardia rotunda, Lea, with V. squamosa, 

 Lam.; Pectunculus obliqua(uus) , Lea, with P. nanus, Desh. ; Ostrea 

 divaricata, Lea, with 0. Jlabellula, Lam.; and Solen Blainoillii, 

 Lea, with Solen effusus, Lam. 



The list herewith appended, and which it is my intention to 

 complete at a future date, will, I trust, increase our knowledge on 

 the interesting questions of relationship and geographical distri- 

 bution. 



