166 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Type in Oldroyd Collection, Stanford University, No. 620-1. Type 
locality, Monterey, California. 
Altitude, 60; diameter, 50 mm., of type; a larger specimen showed 
altitude, 80; diameter, 60 mm. 
Range. Monterey, California. This shell has been called Astraea 
inaequalis, by collectors, but differs enough to be given a subspecific name. 
The range of the typical species is Vancouver Island, British Columbia, to 
San Pedro, California. That of Avar, pacifica Dali, Pacific Beach, San 
Diego County, California. 
Astraea barbarensis Dali, 1919 
Proceedings of the United States National Museum, 56:357. 
Shell of moderate size, trochiform, white, covered by a reddish-brown 
periostracum, with six or more flattish whorls, the nucleus defective; 
suture rather obscure, not appressed; axial sculpture of (on the last whorl 
about 30) rounded, protractively oblique ribs, with equal or wider inter¬ 
spaces, reaching from the suture to the periphery which they undulate; 
halfway from the suture to the periphery these are cut into segments by 
three deeply incised grooves; there may be, near the periphery, a few 
intercallary short ribs; there are also fine, close, inconspicuous, incremental 
lines; on the base inside the undulate border are five strong regularly 
beaded cords with narrower channeled interspaces; aperture subquadrate, 
the upper part of the outer lip much produced; the body glazed, the pillar 
concavely arcuate, ending in a blunt projection, behind it a porcellanous 
white semilunar callus around the imperforate umbilical depression. Height 
of shell, 26; of aperture, 12; diameter, 37 mm. (Dali.) 
Type in United States National Museum, No. 223819. Type locality, 
U.S. Fish Commission Station 2945, off Santa Cruz Island, California. 
Range. Known only from type locality. 
Genus LEPTOTHYRA (Carpenter) Pease, 1869 
Shell small or minute, globose-depressed, solid, compact; umbilicate or 
imperforate, whorls three to seven, spirally sculptured, the last generally 
somewhat deflexed at the aperture; aperture subcircular, white and nacre¬ 
ous within; columella generally but not always bluntly denticulate near the 
base. Operculum subcircular, nearly flat or concavo-convex, inside with a 
very thin corneous layer, slightly convex, with many gradually increasing 
whorls, the nucleus subcentral; outside calcareous, subspiral, with a slightly 
convex concentric elevation or ridge around the margin, most prominent 
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