Cephalopoda of the Cincinnoti Group. 



133 



.side, 2.18 inches. Ti-ansverse diameter of the small end, 2.54 inches; 

 of the chamber habitation, 2.90 inches. Diameter of siphuucle, 0.52 inch. 



Fig. 17. — Cyrtoceras obscura. LoDgitudiual section showing part o£ the siphunele. 



I found this specimen in the first ward of Cincinnati, about 130 feet 

 above low water-mark. 



For Cyrtoceras Vallandighami (S. A. Meller), see vol. i., p. 232, 

 of this Joui-nal, July, 1874. 



Trochcceras (?) Baeri — (IMeek and Worthen, 1865). 



Shell sub-di.scoidal, consistmg of about two or three rather rajiidly 

 enlarging volutions, Avhich are more broadly rounded on the outer 



