224 PROCEEDINGS OF THE ACADEMY OF [1879. 



tortiplica is somewhat more slender and elevated. As this may 

 be only an accidental feature in the few examples which have come 

 under my notice, I feel but little hesitation in uniting the two as 

 one species. Bronn and Nyst (p. 477) refer with some doubt the 

 G. parva of Lea to Brander's type, but this diminutive Alabama 

 species has only two plaits on the columella, and is destitute of 

 varices. 



Niso umbilicata, Lea. Contr., p. 103, as Pasithea. 

 Niso terebellatus, Lamk. 



I have been unable to detect the slightest difference between 

 specimens obtained from both species. 



Sigaretus canaliculars, Sow. Min. Conch., iv., p. 115. 



This shell is mentioned by Conrad (Foss. Shells of Tert., 2d ed., 

 p. 34) as occurring at Claiborne, Ala. It is probably identical 

 with S. declivus and S. bilix, Con., which differ among themselves 

 about as much as they do from the European species. 



Solarium ornatum, Lea. Contr., p. 120. 



This species is placed without doubt by Bronn (ii., p. 1153) as 

 synonymous with S. canaliculatum, Lam. The description and 

 figures as given by Desires (Coqu. Foss., ii., p. 221) answer per- 

 fectly to the American species, and I feel no doubt but that an 

 examination of specimens of both species will prove their identity. 

 The S. canaliculatum is mentioned by Conrad (Foss. Shells of 

 Tert., 2d ed., p. 34) as occurring in the Alabama Eocene deposits. 



Pleurotoma denticula, Bast. Descrip. Geol. du Bass. Ter. Sud-ouest de la France, 

 1825, p. 63. 



On a comparison of specimens of the P. nodo-carinata, Gabb 

 (J. A. N. S., 2d series, vol. iv., p. 379), with the exhaustive analysis 

 of the above species as given by Mr. F. E. Edwards in his " Mono- 

 graph of the Eocene Mollusca" of England (Reports of the 

 Palasontographical Society), 1 feel no hesitation in including it 

 among the numerous varieties of Basterot's species. No mention 

 is made by Gabb of a division of the central crenulation into a 

 double series, but at least some of the specimens deposited in the 

 Academy Museum, and marked with his specific name, show this 

 feature distinctly. The P. denticula is a very widely distributed 

 species of Pleurotoma, its range in Europe extending from Eng- 

 land through Belgium ( Nyst, u Goqu. et Pol. Foss." p. 526) and 

 France (Basterot, sup.; Grateloup " Gonchyl. Foss. des Terr. Ter.," 



