180 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
only project. Post-nuclear whorls flattened, marked by three equal and 
equally spaced, strong, spiral keels, of which one is at the summit and 
another about as far above the periphery as the space which separates it 
from the median keel. The spaces between the spiral keels are deep, 
rounded grooves, almost as wide as the keels and crossed by numerous, 
slender, axial threads. Sutures deeply channeled; channels a little more 
profound than those between the keels. Periphery of the last whorl marked 
by a sulcus. Base short, well-rounded, and marked by four, subequal and 
subequally spaced, spiral cords, the spaces between which appear as rather 
broad sulci and are crossed by slender axial threads. Aperture small, very 
oblique, ovate; posterior angle obtuse; outer lip thin, showing the external 
sculpture within; inner lip short, curved, slightly revolute, provided with 
a strong fold at its insertion; parietal wall glazed with a thin callus. 
Length, 3.1; diameter, 1.4 mm. (Bartsch.) 
Type in United States National Museum, No. 211561. Type locality, 
San Diego, California. 
Range. San Diego, California, to San Hipolito Point, Lower Cali¬ 
fornia. 
Odostomia harfordensis Dali and Bartsch, 1907 
Plate 57, fig. 5 
Proceedings of the United States National Museum, 33 :521; PI. 46, fig. 5. 
Shell elongate-ovate, bluish-white. Nuclear whorls smooth, obliquely 
immersed in the first of the succeeding turns, only two-thirds of the last 
volution projects above them. Post-nuclear whorls well-rounded, and 
somewhat inflated, marked by numerous incremental lines and 5, equally 
strong, but irregularly distributed, punctate, incised, spiral lines between 
the sutures. The two near the summit are placed closer to each other than 
any of the others, the space between the summits and in the second line 
being about equal to the space inclosed between the first and second 
supraperipheral lines. The third line falls on about the middle of the 
exposed portion of the whorls and is a little nearer to the second line than 
the one anterior to it. In addition to these 5 strongly incised lines there 
are numerous very fine and closely spaced spiral striae which cross all 
parts of the surface of the shell. Periphery and base of the last turn 
inflated, the latter marked by lines of growth and 8 strongly incised, 
punctate spiral lines, which are a little less strongly impressed and a 
little more closely spaced at the umbilical area than at the peripheral part 
of the base. These lines equal those of the spire in strength. Sutures 
constricted. Aperture very large, somewhat effuse anteriorly; posterior 
angle acute; outer lip thin, showing the external sculpture within; colu- 
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