CLASS GASTROPODA 
183 
volution projects. Post-nuclear whorls well-rounded, feebly contracted at 
the suture, appressed at the summit. Suture slightly impressed. Periphery 
obscurely angulated. Base well-rounded. Entire surface marked by 
slightly retractive lines of growth and exceedingly fine spiral striations. 
Aperture ovate, posterior angle acute; outer lip thin; columella strongly 
curved, decidedly revolute, provided with a strong fold at its insertion. 
Length, 3 ; diameter, 1.5 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 206923. Type locality, 
United States Bureau of Fisheries Station 2936, in 359 fathoms, off San 
Diego, California. 
Range. Known only from type locality. 
Odostomia amchitkana Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 210; PI. 24, fig. 7. 
Shell broadly conic, thin, semitranslucent, bluish-white. Nuclear whorls 
very obliquely immersed in the first of the succeeding turns, above which 
only the last half of the last turn is visible. Post-nuclear whorls well- 
rounded, faintly shouldered at the summit, marked by fine lines of growth 
and numerous, very fine, equal and equally spaced, spirally incised lines, 
of which there are probably more than forty between the periphery and 
the summit of the last turn. Sutures rendered subchanneled by the slight 
shoulder at the summit of the whorls. Periphery and base of the last 
whorl well-rounded, the latter somewhat attenuated and marked like the 
spaces between the sutures. Aperture large, broadly pear-shaped, posterior 
angle obtuse; outer lip broadly recurved, thin, showing the fine external 
striation within; columella slender, curved, and revolute; re-enforced by 
the attenuated base and provided with a weak fold at its insertion, which 
is not visible when the aperture is viewed squarely; parietal wall glazed 
with a thin callus. Length, 3.3; diameter, 1.7 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 161088. Type locality, 
Constantine Harbor, Amchitka Island, Alaska. 
Range. Amchitka Island, Aleutian, to Peril Strait, Alaska. 
Odostomia angularis Dali and Bartsch, 1907 
Plate 66, fig. 2 
Proceedings of the United States National Museum, 33:523; PL 47, fig. 2. 
Shell very regularly elongate-conic, subdiaphanous to milk-white. 
Nuclear whorls small, deeply obliquely, immersed in the first of the suc¬ 
ceeding turns, above which the tilted edge of the last turn only is visible. 
Post-nuclear whorls slightly rounded, separated by constricted sutures, 
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