GASTROPODA— NATICIDJE. 



719 



body whorl somewhat depressed-convex ; aperture ovoid ; inner 

 lip expanded over umbilical region. 



Claibornian of Alabama ; Upper Eocenic of Mississippi. 



381. N. (Cryptonatica) floridana Dall. (Fig. 1043.) Oligocenic. 

 Differs from N. duplicata in its somewhat more globular form, 



more elongate aperture, and smaller callus ; from N. Jieros, in its 

 smaller size, absence of shoulder concavity or flattening, somewhat 

 narrower aperture, and the callus. 



Chipolan and Orthaulax beds of Florida. 



382. N. (Lunatia) heros (Say). Miocenic-Recent. 

 Large, with globular whorls strongly embracing, and generally 



slightly depressed below the suture, especially in adult ; umbilicus 

 large, scarcely encroached upon by callus of inner lip. 



Chesapeake group of Atlantic coast ; Pliocenic of southern 

 United States ; Pleistocenic of South Carolina and Canada. Widely 

 distributed on modern Atlantic coast of North America. 



383. N. (Neverita) duplicata. Miocenic-Recent. 

 Strongly embracing, spire with scarcely impressed sutures ; 



callus of inner lip large, nearly or quite covering the umbilicus. 



Chesapeake of Atlantic coast ; Pliocenic of southern United 

 States ; Pleistocenic of Atlantic coast from Virginia south ; Recent 

 from Massachusetts Bay southward. 



CXIV. Gyrodes Conrad. 

 Naticoid shells with broad and deep umbilicus generally sur- 

 rounded by an angulation, and a flattened or concave band at the 

 suture in the later whorls. Cretacic. 



384. G. depressa Meek. (Fig. 1044, a.) Cretacic. 



Fig. 1044. a, Gyrodes depressa ; &, c, G. conradi. (After Stanton.) 



Spire depressed or somewhat elevated. Body whorl rapidly 

 enlarging, subangular or narrowly rounded below, with large um- 

 bilicus ; aperture ear-shaped. 



