CLASS GASTROPODA 
169 
Odostomia vicola Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 153; PI. 16, fig. 11. 
Shell ovate, vitreous. Nuclear whorls large, deeply immersed in the 
first of the succeeding turns, above which the tilted edge of the last 
volution only projects, which is marked by five slender spiral threads. 
Post-nuclear whorls rounded on all but the first whorl, marked by very 
broad, strong, retractive axial ribs, of which sixteen occur upon the 
second and third and twenty upon the penultimate turn. In addition to 
the axial ribs the whorls are marked by four, very broad, low, spiral cords, 
which are separated by mere incised lines between the sutures, which 
render their junction with the axial ribs very strongly nodulous. Sutures 
constricted, showing a portion of the peripheral cord. Periphery of the 
last whorl marked by a strong, well-rounded, spiral cord. Base of the last 
whorl decidedly attenuated, marked by seven subequal spiral cords, the 
spaces between which are marked by numerous, slender, axial threads. 
Aperture elongate-ovate, decidedly effuse anteriorly; posterior angle acute; 
outer lip thin, showing the external sculpture within, rendered sinuous by 
the spiral cords; columella long, moderately strong, somewhat sinuous, 
reflected, re-enforced by the base, and provided with a fold at its insertion. 
Length, 2.5; diameter, 1.2 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 206899. Type locality, 
San Pedro Bay, California. 
Range. Known only from type locality. 
Odostomia vincta Dali and Bartsch, 1909 
Plate 59, fig'. 4 
Bulletin 68, United States National Museum, 165; PI. 17, fig. 4. 
Shell elongate-ovate, white. Nuclear whorls deeply obliquely immersed 
in the first of the succeeding turns. Post-nuclear whorls flattened, strongly 
contracted at the periphery, well-shouldered at the summit, marked by 
strong, somewhat retractive, axial ribs, which terminate at the posterior 
edge of the first supraperipheral keel, which is smooth. Of these ribs, 
eighteen occur upon the second, twenty upon the third, twenty-two upon 
the fourth, and twenty-seven upon the penultimate turn. In addition to 
the axial ribs the whorls are marked by four spiral keels, which equal the 
ribs in strength and render their junction nodulous. The spaces inclosed 
by the axial ribs and spiral cords are well-impressed round pits. Sutures 
strongly channeled. Periphery of the last whorl marked by a strong 
groove. Base of the last whorl well-rounded, marked by five spiral cords, 
which grow successively a little weaker from the periphery to the umbilical 
The spaces between these cords are marked by slender spiral threads 
[ 467 ] 
area. 
