WEST AMERICAN PYRAMIDELLID MOLLUSKS. 223 



ODOSTOMIA (AMAURA) KRAUSEI Clessin. 



Plate 29, fig. 5. 



Odostomia hrausei Clessin, Mart. Chem. Conch. Cab., 2d ed.. Pyramid., 1900, 

 p. 115, pi. 28, fig. 1. Odostomia {Amaura) Jcrausei (Clessin) Dall and 

 Bartsch, Proc. U. S. Nat. Mus., vol. 30, 190G, p. 362, pi. 23, fig. 2. 



Shell elongate-conic, thick and heavy, rough through erosion, yel- 

 lowish white. (Nuclear whorls decollated in the type, judging from 

 the pit in the apex they are probably deeply, oblic(uely immersed.) 

 Post-nuclear whorls only moderately rounded, somewhat shouldered 

 at the summit (surface decidedly eroded). Periphery and base of the 

 last whorl well rounded, the latter with a minute umbilical chink. 

 Aperture auricular, somewhat effuse anteriorly, posterior angle 

 scarcely acute; outer lip very thick, reflexed, pillar with a broad, 

 strong, oblique fold, a little anterior to its insertion; parietal wall 

 covered by a thick callus. 



The type has six post-nuclear whorls, and measures: Length 

 9.9 mm., diameter 5 mm. It was collected by Krause at Killisnoo, 

 which is in Alaska, antl not in Japan, as stated by Clessin. The regis- 

 tration number of his type in the Berlin Museum is also wrong; the 

 specimen described and figured by him is Cat. no. 36335, and not 

 Cat. no. 36336, as given in his account of the species. 



The U. S. National Museum has two lots, one specimen (Cat. no. 

 159454, U.S.N.M.) from Killisnoo, collected by Krause, and another 

 (Cat. no. 159471, U.S.N.M.) from Kadiak. 



The last is in better state of preservation than the rest of the 

 material examined; from it we learn that the whorls are strongly 

 rounded, subtabulate at the summit and decidedly constricted at 

 the sutures, marked by fine, slightly retractive lines of growth and 

 exceedingly fine, closely spaced, microscopic spiral striations. Our 

 figure is made from this specimen, which has seven post-nuclear 

 whorls, which measure: Length 8.8 mm., diameter 4 mm. 



ODOSTOMIA (AMAURA ) ORCIA, new species. 

 Plate 27, fig. 3. 



Shell elongate-ovate, narrowly umbilicated, yellowish-white. 

 Nuclear whorls small, deeply immersed in the first of the succeeding 

 turns, above which only the tilted edge of the last volution projects. 

 Post-nuclear whorls well rounded, moderately contracted at the 

 sutures, and narrowly shouldered at the summit, marked by numerous 

 closely spaced, wavy, spiral striations. Periphery and base of the 

 last whorl inflated, well rounded, the latter narrowly umbilicated, 

 both marked by spiral sculpture like that of the spire. Aperture 



