112 PROCEEDINGS OF THE ACADEMY OF [1884. 



2. Dentalium thallus Conr., of the Miocene of the Southern States 

 (Journ. Ac. Nat. Sc. Philarl., vol. vii, 1st series, 1834, p. 142). The 

 specimens of this species in my possession have a circular section, 

 except at the aperture, where they are oval. It is the opinion of 

 ProfessorVerrill and of myself, that Cadulus Pandionis Verrill and 

 Smith (A. E. Verrill, Catal. of Mar. Moll., Transact. Connect. Ac, 

 vol. V, part. 2, 1882, p. 558, tab. 58, fig. 30 a) of the western part 

 of the Atlantic is identical with this Cadulus thallus Conr., 

 • although the latter form has the aperture generallj'^ a little more 

 oval. If Jeffreys is right (J. G. Jeffreys, " On the Moll, of the 

 Lightning and Porcupine expedition," part v) in uniting Cadulus 

 Pandionis Verrill and Smith, with Cadulus Olivi Scacchi from 

 the Pliocene of Sicily, it would result that both late Tertiarj"- 

 species are also identical, and this would be one more instance 

 of a Tertiary species occurring on both sides of the Atlantic. 



3.' Ditrupa suhcoarcuata Gabb, Eocene of Texas (Journ. Ac. 

 Nat. Sc. Philad., vol. ix, 2d series, 1860, p. 386, tab. 6T, fig. 47). 

 The description of Gabb is the following : " Arcuate, widened in 

 advance of tlie middle; aperture contracted, circular; surface 

 polished." As Gabb does not say anything about an oval section, 

 but on the contrary writes "aperture circular," it is apparently a 

 different species. 



