NO. 2 PYRAMIDELLID MOLLUSKS — BARTSCH 89 



whorls are much wider at the periphery than at the summit ; they are 

 poHshed and without sculpture. The suture is well impressed. The 

 summit of the whorls falls immediately below the weak angulation of 

 the periphery. The base is rather short, well rounded, narrowly um- 

 bilicated, and without sculpture. The aperture is rather short and very 

 broadly oval ; the columella is slender, oblique, slightly reflected at the 

 edge and provided with a strong fold a little below its insertion ; the 

 parietal wall is glazed with a thin callus ; and the outer lip is strongly 

 curved. 



The type, U.S.N.M. No. 561729, comes from the Pliocene of North 

 St. Petersburg, Fla. It has 6.3 postnuclear whorls and measures : 

 Length 3.2 mm., diameter 1.8 mm. U.S.N.M. No. 561730 contains 

 three additional specimens from the same source, and three more are 

 in the collection of the A.N.S.P. 



The much stouter shape will easily distinguish this species from 

 Odostomia stephensoni (below), which also has an angulated pe- 

 riphery. 



This species is named for William M. Gabb, who made conspicuous 

 contributions to West Indian paleontology. 



ODOSTOMIA (ODOSTOMIA) STEPHENSONI, new species 

 Plate 17, figure 7 



Shell small, elongate-ovate, cream-yellow. The nucleus is deeply 

 immersed in the first postnuclear whorl above which the tilted edge 

 of the last whorl only projects. The postnuclear whorls are slightly 

 rounded; the summit of succeeding whorls falls a little below the 

 peripheral angulation and thereby lends emphasis to the well-marked 

 suture. The whorls are polished and without sculpture. The periphery 

 is weakly angulated. The base is hemispherical, very narrowly um- 

 bilicated, and without sculpture. The aperture is obliquely oval; the 

 columella is oblique, slightly reflected at the edge, and bears a strong 

 fold a little below its insertion; the parietal wall is glazed by a thin 

 callus; and the outer lip is evenly curved. 



The type, U.S.N.M. No. 561731, comes from the Pliocene of North 

 St. Petersburg, Fla. It has 5.3 postnuclear whorls and measures : 

 Length 2.7 mm., diameter i.i mm. Another specimen from the same 

 source is in the collection of the A.N.S.P. 



The much more slender shape will easily distinguish this species 

 from Odostomia gabbi (p. 88). 



This species is named for Lloyd W. Stephenson, whose studies 

 carried the pyramidellids into the Cretaceous. 



