692 



NORTH AMERICAN INDEX FOSSILS. 



275. C. bellatulum Hall. (Fig. 986.) Devonic. 

 Whorls (six or seven) round to flattened on the shoulder and 



subangular below. In form and size like Cyclonema bilix, but 

 readily distinguished by its transverse striae. 



Onondaga of northern Ohio, Michigan, and Falls of the Ohio. 



276. C. lichas Hall. Devonic. 



Fig. 986. Callonema bellatulum. (After 

 Hall, Pal. N. Y.,V.) 



Fig. 987. Callonema humile. 

 (After Meek, Pal. Ohio, I.) 



Larger, with larger apical angle and last volution more ventricose. 

 Onondaga of New York and Ohio and Falls of the Ohio. 



277. C. humile Meek. (Fig. 987.) Devonic. 

 Spire broad and low ; whorls strongly embracing, rounded, and 



rapidly enlarging ; striae finer and more crowded on adult por- 

 tion than in preceding. 



Onondaga of Ohio and Falls of the Ohio. 



LXXX. Isonema Meek and Worthen. 

 Differs from Callonema in its compressed whorls and angular 

 periphery, and in the obsolescence of the striae below the angula- 

 tion. Devonic. 



278. I. depressum M. and W. Devonic. 

 Small, depressed, whorls embracing above periphery. 

 Hamilton of Illinois. * 



LXXXI. Loxonema Phillips 



Turreted shells, the high spire of many whorls, non-umbilicated ; 

 transverse striae forming a double curve. Siluric ?-Carbonic. 

 279. L. robustum Hall. Devonic. 



Robust, last volution ventricose, nearly an inch in diameter, 

 length about 4 inches. 



