104 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
rounded, not quite equal and equally spaced spiral cords, which are about 
as wide as the spaces that separate them, and numerous, fine lines of 
growth and microscopic, closely spaced, spiral striations. The incremental 
lines and fine spiral sculpture give to the surface of the shell a fine cloth¬ 
like texture. Suture strongly constricted. Periphery of the last whorl 
inflated, well-rounded. Base short, strongly rounded, narrowly umbilicated, 
marked by 14 spiral cords which become a little less strong and closer 
spaced anteriorly. In addition to this the base is marked by the fine 
sculpture referred to on the spire. Aperture subcircular, posterior angle 
decidedly obtuse; outer lip thin, strongly curved, showing the external 
sculpture within; columella slender and slightly reflected; parietal wall 
covered by a thick callus which renders the peritreme complete. 
Type in United States National Museum, No. 362154. Type locality, 
Shuyak Straits, Afognak Island, Alaska. Length, 2.5 mm.; diameter, 
1.3 mm. 
Family RISSOINIDAE 
Genus RISSOINA Orbigny, 1840 
Rissoiform, ribbed or cancellated, whorls numerous, apex mamillated ; 
aperture semilunar, lip thickened within, a little reflected, anteriorly effuse 
or faintly channeled. Operculum corneous, thick, semilunar, paucispiral, 
with a claviform process on the internal face. (Tryon, Manual of Con - 
chology.) 
Type. Rissoina cate shy ana Orbigny. 
Distribution. World-wide. 
Rissoina kelseyi Dali and Bartsch, 1902 
Nautilus , 16:94. Proceedings of the United States National Museum , 49:49; PI. 30, 
fig. 4. 
Shell of medium size, elongate-conic, white, variously banded, or uni¬ 
formly chocolate brown. Nuclear whorls mamillate, smooth. Post-nuclear 
whorls slightly rounded, ornamented axially by a few broad, depressed, 
almost obsolete ribs, which are best seen near the summit of the whorls, 
and many irregular, more or less deeply impressed striations, which 
extended almost undiminished to the umbilical region. The spiral sculp¬ 
ture, however, is more conspicuous than the axial, and consists of deeply 
impressed lines which are more closely placed and less strongly developed 
near the summit of the whorls than at the periphery, grading gradually 
in this respect between these two regions. Sutures simple, well-marked. 
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