64 Geological Survey of Alabama. 



aperture. The aperture is wanting in Conrad's specimen of Dentalium 

 arciformis. Later, Conrad withdrew this species ; at least he did not 

 mention it in his lists, probably considering his form a synonym of Dent- 

 alium turritum, Lea,* which species, however, in my opinion, is a frag- 

 ment of a Cadulus. 



DENTALIUM DANAI, Meyer. PI. 3, figs. 2, 2a. Am. Jour. Sci., 

 1885, XXIX., p. 462. 



Smooth, section circular ; smaller aperture with additional tube ; mar- 

 gin distinctly notched on the convex side of the shell ; slightly emargin- 

 ate on the concave side 



Locality. Jackson, Miss. 



The preceding species is notched distinctly on both sides of the margin 

 of the aperture. 



DENTALIUM SUBCOMPRESSUM, Meyer. PL 3, figs. 3, 3a. Am. Jour. 

 Sci., 1885, XXIX., p. 462. 



Shell small, smooth, somewhat polished ; section ovate. 

 Locality. Jackson, Red Bluff, and Vicksburg, Miss. . 

 The figured type-specimen is from Jackson. 



DENTALIUM BITUBATUM, n. sp. pi 3, fig. 1. 



Smooth, rapidly increasing in size; section suborbicular ; aperture with 

 a long additional tube. 



Locality. Jackson, Miss. 



I have only one specimen of this species, which in its long tube of the 

 aperture resembles Dentalium duplex, Def.f from the Paris basin. 



DENTALIUM ANNULATUM, n. sp. PI. 1, fig. 1. 



Small, slightly tapering; section circular; surface annulated. 



Locality. Claiborne, Ala. 



I found only the figured specimen. Without a magnifying glass the 

 characteristic rings of the surface are scarcely to be seen. It is verJ 

 similar to young specimens of Dentalium minutistriatum, Gabb.,J which 

 species is annulated on its youngest part, a fact not mentioned by Gabb. 



*I. Lea, Contrib. to GeoL, 1833, p. 35, pi. 1, fig. 3. 



tDesh., An. s. verteb., II., p. 203, pi. 1, figs. 36-3!). 



% Jour. Acad. Nat. Sci., Phila., IV., 2d ser., I860, p. 386, plate 67, fig. 46. 



