﻿NEW CRETACEOUS AND EOCENE FOSSILS. 289 



shells and rounded, callous columella. I propose to class them in a subgenus under 

 the name of Nereis. 



NATICA, Lam. 



Subgenus GYRODES, Conrad. 



Globose, thin in substance ; whirls channelled above ; umbilicus profound, without 

 a callus on the columella or base. 



A group of thin-shelled Cretaceous forms of the Naticidae family, casts of which 

 have long been familiar to us from the New Jersey deposits. Natica petrosa, Morton, 

 belongs to the subgenus. 



N. (Gyrodes) crenata. Channel on the spire rather wide, not profound; apex 

 flattened ; shoulder obliquely plicated ; umbilicus patulous, carinated within near the 

 base, and the periphery acutely carinated and crenulated ; volutions visible to the 

 apex in the umbilicus. 



Locality. — Tippah Co., Mississippi. Dr. Spillman. 



A species remarkable for the size of umbilicus and its acute, crenulated margin. 



N. (Gyrodes) alveata. PI. 46, fig. 45. Channel of spire wide and margined by a 

 carina ; spire slightly prominent, apex acute ; whirls slightly contracted below 

 the carina, five in number; umbilicus moderate in diameter, without a revolving 

 line. 



Locality. — Occurs with the preceding. Dr. Spillman. 



TURBINOPSIS, Conrad. 



Turbinate; spire conical; whirls channelled at the suture; umbilicus profound; 

 inner and outer lip continuous above and separated from the body whirl ; columella 

 concave with a very oblique fold near the basal margin. 



There appear to be two or more species of this genus in the Cretaceous strata of 

 New Jersey, occurring in the state of casts, one of which I think is identical with the 

 present shell. This genus is allied to Cancellaria, Lam. 



Turbinopsis Hilgardi. PL 46, fig. 29. Turbinate; whirls of spire four or five, 

 subangular ; shell with prominent, flattened, revolving ribs below the angle of each 

 whirl, above are unequal, rugose, impressed lines ; eight ribs on the body volu- 

 tion, and a few striae near the margin of the umbilicus, which is very wide and 

 exhibits the volutions to the apex ; umbilical margin acute and salient ; aperture 

 suboval. 



Locality. — Tippah Co., Mississippi. Dr. Spillman. 



TUBA? Lea. 

 Tuba? bella. PI. 46, fig. 38. Turrited; whirls nine, rapidly increasing in size, 



