GASTROPODA— APORRHAWM. 



753 



Claibornian and Jacksonian of the Gulf States ; the variety- 

 occurs in the Midway horizon of the Gulf States from Georgia to 

 Texas. 

 497. C. trinodiferus Conrad. (Fig. 1095, a } b.) Eocenic. 



FlG. 1095. a, b, Calyptraphorus trinodiferus; c, d, C. jacksoni. (All X %- ) 



(Md. Survey.) 



With ornamentation of early whorls faint, and with great pro- 

 longation of the reflected upper angle of the lip. 



Pamunkey formation of Atlantic coast. Lignitic (Chickasawan) 

 of Alabama and Texas. 

 498. C. jacksoni Clark. (Fig. 1095, c, d.) Eocenic. 



Large, solid, whorl wholly covered by subsequent expansions. 



Aquia of Atlantic coast. 



CXXXVII. Aporrhais da Costa. 



Like Anchura but lip with posterior canal either closely adher- 

 ing to the spire, or free from same ; outer lip expanded, lobed or 

 digitate. Jurassic-Recent. 



499. A. (Perissoptera) prolabiata White. (Fig. 1096, a.) 



Cretacic. 



Spire with rounded whorls marked by roifnded ribs more than 

 their width apart ; lip with strong, acute spine, separated by a 

 rounded sinus from the broader subquadrate portion of the lip ; 

 expansion of lip partly covering penultimate whorl. 



Colorado formation of Utah and New Mexico (?). 



