WEST AMERICAN PYRAMIDELLID MOLLUSKS. 219 



Shell not umbilicated — Continued. 



Shell less than 10 mm. long — Continued. 

 Shell ovate. 



Summit of the whorls appressed nuciformis, p. 227. 



Summit of the whorls tabulated. 



Adult shell more than 9 mm. long canfieldi, p. 228. 



Adult shell less than 7 nmi. long subturrita, p. 228. 



Shell very broadly ovate martensi, p. 229. 



ODOSTOMIA (AMAURA) LASTRA, new species. 



Plate 28, fig. 7. 



Shell thin, large, elongate-ovate, tapering very regularly to an 

 acute point, narrowly umbilicated. Nuclear whorls very small, 

 deeply obliquely immersed in the first of the succeeding whorls, above 

 which only the tilted edge of the last volution projects. Post-nuclear 

 whorls well rounded, moderately constricted at the sutures and nar- 

 rowly shouldered at the summit, marked by numerous slender wavy 

 spiral striations and fine lines of growth which give the surface a 

 somewhat malleated appearance. Periphery and base of the last 

 whorl strongly rounded, the latter narrowly umbilicated, marked 

 like the spire. Aperture large, broadly oval, slightly effuse anteriorly; 

 posterior angle acute; outer lip thin; columella slender, very oblique, 

 almost straight and somewhat reflected; parietal wall glazed with a 

 thin callus. 



The type (Cat. no. 206928, U.S.N.M.) was dredged at U. S. Bureau 

 of Fisheries station 2917, in 90 fathoms, temperature 49°. 1, off 

 southern California. It has eight post-nuclear whorls and measures: 

 Length 13.6 mm., diameter 7 mm. Other specimens examined are 

 as follows: One, Cat. no. 170794, U.S.N.M., from Santa Catalina 

 Channel, California; one dredged by University of California at sta- 

 tion 21 (3), off Santa Catalina Island, University of California coll.; 

 one dredged by University of California at station 30, off Santa Cata- 

 lina Island, University of California coll. ; one dredged by University 

 of California at station 81, off San Diego, University of California coll. 



ODOSTOMIA (AMAURA) KENNERLEYI Dall and Bartsch. 



Plate 28, fig. 8. 



Odostomia (Amaura) kennerleyi Dall and Bartsch, Proc. U. S. Nat. Mus., vol. 

 33, 1907, p. 529, pi. 48, figs. 8, 8a. 



Shell large, very thin, broadly conic, umbilicated, yellowish-white; 

 marked by subobsolete, subequal, and subequally spaced spiral 

 wrinkles, about fifteen of which may be seen on the body and base of 

 the last whorl. In addition to these wrinkles, many faint, closel}'' 

 placed spiral and vertical striae are present. Nuclear whorls small, 

 about two and one-half, forming a depressed spire wliich is deeply 

 immersed, the axis of which is almost at right angles to the axis of 



