CLASS GASTROPODA 
209 
Sutures somewhat constricted. Aperture moderately large, oval; posterior 
angle obtuse; outer lip thin; inner lip rather long, slightly curved, and 
somewhat revolute, provided with a strong fold at its insertion; parietal 
wall glazed with a thin callus. Length, 4.7; diameter, 2.2 mm. (Bartsch.) 
Type in United States National Museum, No. 211556. Type locality, 
San Pedro, California. 
Range. Known only from type locality. 
Odostomia tillamookensis Dali and Bartsch, 1907 
Plate 66, fig. 1 
Proceedings of the United States National Museum, 33:522; PI. 47, fig. 1. 
Shell elongate-conic, thin yellowish-white. Nuclear whorls surrounded 
by the first of the succeeding turns and so immersed as to give the apex 
a broadly truncated appearance. Post-nuclear whorls inflated, evenly 
strongly rounded, very slightly shouldered at the summit, separated by 
well-marked sutures. Periphery and base of the last whorl well-rounded, 
the latter inflated, narrowly openly umbilicated. Entire surface marked 
by numerous fine, wavy, subequal, weakly incised, spiral lines, of which 
about 35 occur between the summit and the periphery of the last whorl 
and about an equal number on the base. Aperture oval; outer lip thin; 
columella slender, evenly gently curved, and slightly revolute, free, not 
re-enforced at the base, provided with a slender fold at its insertion, which 
is not visible when the aperture is viewed squarely. Length, 4.1; diame¬ 
ter, 2.2 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 196244. Type locality, 
United States Fisheries Steamer “Albatross” Station 3346, off Tillamook, 
Oregon, in 786 fathoms. 
Range. Known only from type locality. 
Odostomia unalashkensis Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 203; PI. 26, fig. 5. 
Shell elongate-ovate, stout and strong, light yellow. (Nuclear whorls 
decollated.) Post-nuclear whorls flattened on their outer three-fourths, 
rounding suddenly to the closely appressed summit, on the posterior 
fourth. Entire surface of the shell marked by lines of growth and 
numerous, equal and equally spaced, well-marked, spiral striations, of 
which about 28 occur between the sutures of the penultimate whorl. 
Sutures well-impressed. Periphery of the last whorl somewhat angulated. 
Base elongated, rounded, marked like the spire. Aperture ovate, slightly 
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