210 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
effuse anteriorly, posterior angle acute; outer lip thin; columella short, 
strongly curved and reflected, re-enforced for the greater part by the 
attenuated base and provided with a strong oblique fold at its insertion; 
parietal wall covered by a thin callus. Length, 4.8; diameter, 2.8 mm. 
(Dali and Bartsch.) 
Type in United States National Museum, No. 150464a. Type locality, 
Captain’s Harbor, Unalaska, Alaska. 
Range. Known only from type locality. 
Odostomia valdezi Dali and Bartsch, 1907 
Plate 63, fig. 6 
Proceedings of the United States National Museum, 33:526; PL 48, fig. 2. 
Shell small, thin, very elongate-oval, subdiaphanous to milk-white, 
having the entire surface marked by rather strong lines of growth and 
numerous microscopic spiral striations. Nuclear whorls deeply obliquely 
immersed in the first of the succeeding turns, above which only the tilted 
edge of the last turn is visible. Post-nuclear turns rather high between 
the sutures, well-rounded, with narrowly roundly shouldered summits. 
Periphery and base of the last turn inflated and well-rounded, the latter 
with a very narrow umbilical chink. Aperture moderately large, oval; 
posterior angle acute; columella strongly curved, re-enforced by the 
attenuated base and provided with a moderately strong fold opposite the 
umbilical chink. Length, 3; diameter, 1.3 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 196249. Type locality, 
off Del Monte, Monterey, California. 
Range. Known only from type locality. 
Odostomia vancouverensis Dali and Bartsch, 1910 
Canada, Department of Mines, Geological Survey Branch, Memoir No. 14-N, 18; 
PL 2, fig. 7. 
Shell elongate-ovate, very narrowly umbilicated, turreted, yellowish- 
white. Nuclear whorls small, obliquely immersed in the first of the suc¬ 
ceeding turns, above which only half of the last volution projects and 
extends beyond the outline of the spire. Post-nuclear whorls broadly, 
tabulatedly shouldered at the summit, moderately rounded, marked by 
almost vertical lines of growth and numerous exceedingly fine spiral 
striations. Sutures rendered very conspicuous by the tabulated shoulder. 
Periphery of the last whorl well-rounded, base moderately long, well- 
rounded, marked like the spire. Aperture large, elongate-ovate, somewhat 
effuse anteriorly; posterior angle decidedly obtuse; outer lip thin; colu- 
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