228 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Shell otherwise exactly like that of E. supravaUata, but always lacking 
the spiral furrow; with angulate base, not carinate. (Translation.) 
Type in United States National Museum. Type locality, San Diego, 
California. 
Range. Monterey to Gulf of California. 
Described as Ethalia var. invallata Carpenter. 
Family SCISSURELLIDAE 
Genus SCISSURELLA Orbigny, 1828 
Shell minute, thin, not pearly; body-whorl large; spire small; surface 
striated; aperture rounded, with a slit in the margin of the outer lip; 
operculate. The young have no slit. (Tryon, Structural and Systematic 
Conchology .) 
Type. Scissurella laevigata Orbigny. 
Distribution. Europe and west coast of North America. Fossil: 
Tertiary. 
Scissurella kelseyi Dali, 1905 
Nautilus, 18:124. 
Shell large for the genus, trochiform, white, with about four rounded 
whorls, sculptured with fine (forwardly convex) arcuate threads or raised 
lines, which above the fasciole are spirally, microscopically striate, and on 
the base, with somewhat regularly spaced and stronger spirals ; the fasciole 
is narrow, slightly above the periphery, bounded by two sharp, very thin, 
elevated keels; the slit extends about one-fifth of the circumference of 
the last whorl. The aperture is nearly circular, interrupted for a short 
distance by the body, the inner lip slightly reflected over a small umbilicus; 
the operculum is multispiral and pale yellow. Alt. of shell, 6.0; of 
aperture, 3.0; max. diameter, 5.5 mm. (Dali.) 
Type in United States National Museum. Type locality, U.S. Fish 
Commission Station 4353, off San Diego. 
Range. Queen Charlotte Islands, British Columbia, to South Coro¬ 
nado Island. 
Scissurella chiricova Dali, 1919 
Proceedings of the United States National Museum, 56:370. 
Shell small, white, trochiform, with a minute subglobular nucleus and 
about four and a half subsequent whorls; spiral sculpture of two sharp 
[830 1 
