﻿Cephalopoda of the Cincinnati Group. 



239 



Locality : Cincinnati, Lebanon, Ohio. 



1 )istinguished by the centrally situated siphuncle in connection with 

 the transverse striae. First described from the Trenton at Watertown, 

 X. Y.. but since found in the vicinity of Cincinnati. 



5. O. TRANSVERSUM, S. A. M. 1875. N 



(Cin. Quar. Jour. Sci. II, 129, fig. 15.) 



Shell medium si/e ; septa arched, distant one-fourth or one-fifth the 

 diameter of the shell; siphuncle eccentric; outer shell thin, marked by trans- 

 verse lines. 



Locality: Columbia Avenue and Eden Park, Cincinnati. 150 to 

 200 feet above low water. 



Somewhat similar to the preceding, but with an eccentric siphuncle. 

 The shell is also larger and the septa more distant. 



6. (). ortoni, Meek. 1872. 



Meek. Pro. Phil. Acad. Nat. Sci., 1872, p. 330. 

 Meek. Ohio Geol. Pal., I, 155, PI. 13, fig. 8. 

 Miller. Cin. Quar. Jour. Sci., II, 130. 



Shell rather rapidly expanding; section oval or circular ; septa close; 

 siphu tide lateral, hut not marginal; surface of cast with traces of regular, 

 obscure, longitudinal ridges ; outer shell unknown. 



Locality : Cincinnati. 



The traces of longitudinal ridges found in this and two of the suc- 

 ceeding species serve to distinguish them from the rest of the species. 

 The rapidly expanding shell and the lateral siphuncle serve to distinguish 

 this species. The figure given in the Ohio Survey is incorrect, as it rep- 

 resents the septa as being separated by elevated lines, which is not the 

 case. 



7. O. anellum (annellus), Conrad. 1845. 



Pro. Acad. Nat. Sci. Philadelphia, I, 334. 



Hall. Pal. of N. Y. I, p. 202, PI. 43, figs. 6a to /. 



' ' Elongated, tapering, with very prominent, not approximate, acute, 

 slightly sinuous transverse ribs, with very fine, crowded, profoundly wrinkled 

 longihidinal lines; siphuncle sub-marginal." 



Locality: Versailles, Ind. 



Distinguished by the prominent transverse ribs. First described from 

 the Trenton of Wisconsin, but it has been found in this group by Mr. C. 

 L. Faber. 



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