﻿244 



Cincinnati Society of Natural History. 



This species attains a very large size and is often flattened by com- 

 pression. The large siphuncle and the large shell are the distinguishing 

 features. 



4. E. APPROXIMATUM, Hall. 1 847. 



(Pal. N. Y., I, p. 219. PI. 54, fig. 2 a.) 



Cylindrical, gradually tapering ; septa with convexity about one- 

 fourth the diameter and distant one-fifth the diameter of the shell ; siphuncle 

 large, marginal, obliquely annulated by the thin edges of the septa. 



Locality : 



The obliquely annulated, large siphuncle is the principle feature of 

 this species. 



5. E. SUB-CENTRALE, Hall. 1 847. 



(Pal. N. Y., I, p. 59. PI. 17, fig. 4.) 



Elongated ; septa rather distant : siphuncle large, sub-central, with 

 external imbricating elevations at the attachments of the septa; septa near 

 siphuncle turn upwards toward apex. 



Locality : 



Genus 4. GOMPHOCERAS, Sowerby. 1839. 



Murch. Silur. Syst. Ill, p. 620. Phragmoceras. Brod. 1839. 



Shell fusiform, or bottle-shaped, sometimes compressed, straight or 

 curved, swollen anterior ; aperture contracted in the middle ; last chamber 

 large; siphuncle dorsal or sub-central; septa simple, concave. (Tryon. 

 Struc, and Sys. Con. II, pp. 54, 55.) 



1. G. eos, Hall & Whitfield. 1875. 



Pal. of Ohio, II, p. 100, PI. 3. fig. 5. 



Shell ovoid, tapering from below upward to middle of outer chamber 

 and contracting above ; outer chamber about one-third entire length of 

 shell, the whole of an elongate crvate form ; septa deeply concave, about one- 

 fifth inch distant. Siphuncle, surface, and aperture, unknown. 



Length \]/ 2 inches, breadth of flattened specimen 3^ inches. 



Locality : Dayton and Waynesville, Ohio, and YVeisburg, Indiana. 



Distinguished by its size, the ovoid form and the concave septa. 



2. G. faberi, S. A. Miller. 1884. 



(J. C. S. N. H. VII, 19, PI. 4, figs. 2, 2 a.) 



G. cincinnatiense, S. A. M. Ibid, p. 19, PI. 4, figs. 1, 1 a. 



Shell small, moderately gibbous ; ventral side convex ; dorsal convex 

 or straight ; transverse section ovoid or elliptical ; siphuncle of medium 



