34 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.65 



marked, slightly constricted. Periphery of the last whorl and the 

 short base well rounded and inflated, the latter narrowly umbili- 

 cated and marked like the spire. Aperture very broadly ovate; 

 posterior angle obtuse; outer lip thin at the edge; inner lip some- 

 what sinuous, reflected over but not appressed to the base, provided 

 with a strong oblique fold ; parietal wall glazed with a thin callus. 



Type. — Cat. No. 352527, N.S.N.M., has 6 postnuclear whorls and 

 measures : Length, 6.2 mm. ; diameter, 3 mm. 



Cat. No. 352528, U.S.N.M., contains 5 specimens from the type 

 locality and there are 10 additional specimens in the Oldroyd 

 collection. 



This form is related to Odostomia {Amaura) helena Bartsch, but 

 is about double the size of that species. The fine spiral striations 

 have been omitted in the figure. 



ODOSTOMIA (AMAURA) TROCHILIA. new species. 



Plate 2, fig. 1. 



Shell broadl}'^ ovate, yellowish white. Nuclear whorls deeply, ob- 

 liquely immersed in the first of the postnuclear turns, above which 

 the tilted edge of the last volution alone projects. Postnuclear whorls 

 well rounded, narrowly tabulately shouldered at the summit, marked 

 only by lines of growth and microscopic spiral striations. Suture 

 constricted. Periphery of the last whorl and the short, narrowly 

 umbilicated base well rounded, marked like the spire. Aperture 

 large, ovate; posterior angle acute; outer lip thin at the edge, thick 

 within ; inner lip somewhat sinuous, reflected over but not appressed 

 to the base, provided with a strong oblique fold a little anterior to the 

 insertion of the columella ; parietal wall glazed by a thin callus. 



Type. — Cat. No. 352529, U.S.N.M., has 5.5 postnuclear whorls and 

 measures : Length, 6.6 mm. ; diameter, 3.2 mm. 



The present form is nearest related to Odostomia {Amaura) eng- 

 hergi Bartsch, from which it differs by its less rounded whorls and 

 little more acutely tabulated shoulder. 



An additional specimen. Cat. No. 352530, U.S.N.M., is likewise in 

 the collection. The fine spiral striations have been omitted in the 

 figure. 



ODOSTOMIA (AMAURA) SANESIA. new species. 

 Plate 1, fig. 13. 



Shell moderately large, elongate conic, yellowish white. Nuclear 

 whorls deeply, obliquely immersed in the first of the succeeding turns. 

 Postnuclear whorls well rounded, narrowly shouldered at the sum- 

 mit, marked by coarse, lines of growth and microscopic spiral stria- 

 tions. Suture moderatel}' constricted. Base short, inflated, with an 



