164 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
little less strongly developed from the periphery to the umbilical area. 
The channels between the cords are crossed by many, very slender, raised, 
vertical threads. Aperture oval, slightly effuse anteriorly; outer lip thin; 
columella re-enforced on its posterior two-thirds by the attenuated base, 
free and somewhat revolute anteriorly; parietal wall glazed by a thin 
callus. Length, 3.3; diameter, 1.2 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 107690. Type locality, 
Cumshewa Inlet, Queen Charlotte Islands, British Columbia, in ten 
fathoms. 
Range. Queen Charlotte Islands, British Columbia, to Monterey, 
California. 
Odostomia pulcherrima Dali and Bartsch, 1909 
Plate 59, fig. 7 
Bulletin 68, United States National Museum, 164; PI. 17, fig. 7. 
Shell large, elongate-oval, vitreous. Nuclear whorls small, smooth, 
deeply obliquely immersed in the first post-nuclear turn, above which only 
the tilted edge of the last volution projects. Post-nuclear whorls strongly 
rounded, decidedly contracted at the sutures and strongly shouldered at 
the summit. The first is marked by four slender spiral cords and numer¬ 
ous, exceedingly fine, axial threads. The next three have twenty, strong, 
rounded, axial ribs, which terminate at the posterior edge of the fourth 
keel, leaving this smooth. On the last whorl the ribs are decidedly 
enfeebled, being replaced by numerous axial threads. The spiral sculpture 
consists of four strong cords between the sutures, the three which cross 
the ribs form strong nodules at their junction with them, while the supra- 
peripheral one is smooth. Suture strongly impressed, slightly channeled. 
Periphery and base of the last whorl well-rounded, marked by eight spiral 
keels, which grow successively weaker from the periphery to the umbilical 
region, the last three being very fine. Spaces separating the cords equal 
to them, crossed by numerous slender, axial threads. Aperture irregularly 
ovate, posterior angle obtuse; outer lip strong, rendered decidedly sinuous 
by the axial ribs; columella short, decidedly twisted, strongly curved, 
reflected, re-enforced by the base and provided with a deep-seated fold at 
its insertion; parietal wall glazed with a thin callus. Length, 5 ; diameter, 
2.3 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 206900. Type locality, 
Terminal Island, San Pedro, California. 
Range. Known only from type locality. 
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