CLASS GASTROPODA 
93 
tween the summit and the first spiral cord on the preceding whorl, thus 
dividing the space between the sutures into five equal portions. The pen¬ 
ultimate whorl has the same spiral sculpture as its predecessor, but in addi¬ 
tion this whorl shows the peripheral spiral cord a little posterior to the 
suture. In addition to these spiral cords, the whorls are marked by 
numerous very fine, spiral striations, which are apparent on the cords and 
in the grooves that separate them. The axial sculpture is reduced to very 
feeble riblets, which are closely spaced and rather irregularly distributed. 
Suture very strongly constricted. Periphery of the last whorl well-rounded. 
Base rather short, umbilicated, marked by six low, rounded, spiral cords, 
which are situated on the posterior two-thirds of the base, and numerous 
fine, closely spaced, spiral striations. Aperture subcircular; posterior angle 
obtuse; outer lip thin, showing the external sculpture within; inner lip 
slender, curved, reflected, but free from the base; parietal wall covered 
with a thick callus which renders the peritreme complete. Length, 2.8; 
diameter, 1.5 mm. (Dali.) 
Type in United States National Museum, No. 213686. Type locality, 
Nunivak Island, Alaska. 
Range. Known only from type locality. 
Alvania montereyensis Bartsch, 1911 
Proceedings of the United States National Museum, 41:343; PI. 30, fig. 2. 
Shell elongate-conic, yellowish-white. Nuclear whorls one and one- 
third, well-rounded, marked by about 8 very slender, spiral lirations, of 
which the three near the summit are weaker than the rest. Post-nuclear 
whorls well-rounded, marked between the sutures by four strong, narrow 
spiral cords, which divide the space between the sutures into five almost 
equal parts, that between the summit and the first cord being a little wider 
than the rest. In addition to the spiral cords, the whorls are marked by 
slender axial riblets, which are about as strong as the spiral cords. Of these 
riblets, about 24 occur upon the first and second, and about 26 upon the 
penultimate turn. The spaces inclosed between the spiral cords and the 
axial riblets are elongated pits, having their long axes parallel with the 
spiral sculpture. In addition to the above sculpture, the entire surface of 
the shell is marked by numerous very fine, closely spaced striations. Suture 
strongly constricted. Periphery of the last whorl marked by a sulcus as 
wide as that which separates the first supraperipheral cord from its pos¬ 
terior neighbor. Base moderately long, scarcely produced anteriorly, well- 
rounded, marked by seven spiral cords, which grow successively weaker 
and closer spaced from the periphery to the umbilical region. Aperture 
moderately large, broadly oval; posterior angle obtuse; outer lip thin, 
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