12 BULLETIN 68, UNITED STATES NATIONAL MUSEUM. 



A' Shells without basal keels — Continued. 

 B' Varices absent — Continued. 



Sphal sculpture present, always stronger than microscopic striations — Con. 

 C Axial sculpture consisting of well developed ribs — Continued. 



Spiral markings consisting of one or two strong cords; whorls some- 

 what overhanging. 



Subgenus Tragula Monterosato, 1884 (16). 

 Type, Odostoniia fenestrata Forbes. 



Spiral markings consisting of three to six raised threads between the 

 sutures and lirations on the base; whorls strongly shouldered. 

 Subgenus Dunkeria Carpenter, 1857 (p. 120). 

 Type, Dunkeria subangulata Carpenter. 



C - Axial sculpture consisting of faint riblets 



Spiral markings consisting of strong raised threads. 

 Subgenus Cingulina A. Adams, 1860 (17). 

 Type, Cingulina cingulata Dunker. 



Spiral sculpture consisting of depressed lirations, sculpture granulose. 

 Subgenus Saccoina, new name (18). 

 Type, Spica monterosatoi Sacco. 



C^ Axial sculpture consisting of lines of growth only. 



Spiral markings consisting of many subequally spaced striations; 

 sculpture finely reticulated. 



Subgenus Careliopsis Morch, 1874 (19) (p. 130). 



Type, Monoptygma (Careliopsis) styliformis Morch. 



C* Axial sculpture absent. 



Spiral markings consisting of a broad strong fold at the summit of 

 the whorls, separated from the rest of the whorl by a deep, broad, 

 rounded sulcus. 



Subgenus Visma Dall and Bartsch (20). 

 Type, Eulimella tenuis Sowerby. 

 B ^ Varices present. 



Surface marked by axial ribs and strong spiral striations. 

 Subgenus Mormula A. Adams, 1864 (p. 110). 

 Type, Mormula rissoina A. Adams. 



Surface marked by axial ribs and strong spiral lirations, sculpture 

 granulose. 



Subgenus Lancella Dall and Bartsch, 1904 (21). 

 Type, Turbonilla (Lancea) elongata Pease. 



A^ Shells with basal keels. 



Axial sculpture consisting of strong ribs. 

 Spiral sculpture absent. 



Subgenus Asmunda Dall and Bartsch (p. 129). 

 Type, Chemnitzia turrita C. B. Adams. 



Spiral sculpture present. 



Spiral sculpture consisting of strong ridges. 

 Basal keels two. 



Subgenus Peristichia Dall, 1889 (22). 

 Type, Peristichia toreta Dall. 



Basal keels three. 



Subgenus Babella Dall and Bartsch, 1906 (23). 



Type, Turbonilla (Babella) cselatior Dall and Bartsch. 



