CLASS GASTROPODA 
201 
contracted at the suture, appressed at the summit, marked by 8 strongly 
incised spiral lines on the first and second and 20 upon the third, between 
the sutures. Suture well-marked. Periphery and base of the last whorl 
well-rounded, marked by numerous spiral striations, which are a little 
weaker than those between the periphery and summit of the last whorl. 
Aperture oval; posterior angle obtuse; outer lip thin; columella moderately 
strong, decidedly curved and strongly revolute, provided with a strong fold 
at its insertion. Length, 3.3; diameter, 1.7 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 196348. Type locality, 
San Pedro Bay, California. 
Range. San Pedro to San Diego, California. 
Odostomia pratoma Dali and Bartsch, 1909 
Plate 63, fig. 4 
Bulletin 68, United States National Museum, 199; PI. 23, fig. 4. 
Shell elongate-ovate, bluish-white. Nuclear whorls deeply obliquely 
immersed in the first of the succeeding turns, above which only the tilted 
edge of the last volution projects. Post-nuclear whorls well-rounded, 
strongly contracted at the sutures, with a rounded sloping shoulder at the 
summit. Periphery obsoletely angulated. Base well-rounded, with an 
obscure umbilical chink. Entire surface of base and spire marked by 
numerous, slightly retractive lines of growth and exceedingly fine, closely 
spaced, spiral striations. Aperture ovate; posterior angle obtuse; outer lip 
very thin; columella slender, strongly curved, slightly revolute, provided 
with a weak, deep-seated fold at its insertion. Length, 2.9; diameter, 
1.4 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 206913. Type locality, 
United States Bureau of Fisheries Station 2902, in 53 fathoms, off Santa 
Rosa Island, California. 
Range. Known only from type locality. 
Odostomia profundicola Dali and Bartsch, 1909 
Plate 60, fig. 8 
Bulletin 68, United States National Museum, 214; PI. 25, fig. 8. 
Shell turreted, milk-white. Nuclear whorls deeply obliquely immersed 
in the first of the succeeding turns, above which only the tilted edge of 
the last volution projects. Post-nuclear whorls moderately rounded, slightly 
contracted at the sutures, broadly tabulately shouldered at the summit. 
Periphery and base of the last whorl somewhat inflated, strongly rounded. 
Entire surface of spire and base marked by numerous vertical lines of 
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