CLASS GASTROPODA 
211 
mella slender, oblique, and somewhat revolute, provided with an oblique 
fold a little anterior to its insertion; parietal wall glazed with a thin callus. 
Length, 4.7; diameter, 2.2 mm. (Dali and Bartsch.) 
Type in Geological Survey Museum, Ottawa, and others in United 
States National Museum, No. 211539. Type locality, ship channel, Barkley 
Sound, Vancouver Island, British Columbia. 
Range. Known only from type locality. 
Odostomia willetti Bartsch, 1917 
Proceedings of the United States National Museum , 52:666; PI. 43, fig. 6. 
Shell large, elongate, conic, bluish-white. Nuclear whorls obliquely 
immersed in the first of the succeeding turns, above which the tilted edge 
of the last volution only projects. Post-nuclear whorls moderately rounded, 
appressed at the summit, the early ones marked by a moderate number of 
strongly incised lines, while on the later whorls the incised spiral lines are 
finer and much more numerous; in addition to the spiral sculpture the 
whorls are marked by decidedly retractively slanting, incremental lines. 
Suture moderately constricted. Periphery of the last whorl inflated, feebly 
angulated. Base attenuated, moderately rounded. Aperture oval, some¬ 
what effuse anteriorly; posterior angle acute; outer lip thin; inner lip 
very oblique, stout, slightly curved, reflected over and appressed to the 
base, provided with a strong oblique fold at its insertion; parietal wall 
covered with a thick callus. Length, 5.8; diameter, 2.4 mm. (Bartsch.) 
Type in United States National Museum, No. 274007. Type locality, 
Waterfall Cannery, west side of Prince of Wales Island, Alaska. 
Range. Known only from type locality. 
Odostomia youngi Dali and Bartsch, 1912 
Proceedings of the United States National Museum, 42:277; PI. 37, fig. 6. 
Shell elongate-conic, umbilicated, milk-white. Nuclear whorls small, 
obliquely immersed in the first of the post-nuclear turns, above which only 
the tilted edge of the last volution projects. Post-nuclear whorls moder¬ 
ately rounded, with a narrow, tabulately shouldered summit, marked by 
equally spaced, rather strong, spiral striations, of which about 32 occur 
between the summit and the periphery on the penultimate turn. Periphery 
and base of the last whorl inflated, well-rounded, marked with spiral 
sculpture equal in strength and disposition to that on the spire. Sutures 
strongly impressed. In addition to the spiral sculpture, the whorls are 
marked with curved retractive lines of growth. Aperture pear-shaped; 
posterior angle acute; outer lip thin; inner lip slender, curved, and some- 
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