258 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
angle very obtuse; outer lip somewhat effuse, rendered decidedly sinuous 
at the edge by the external sculpture; columella very strong; inner lip 
reflected and appressed to the columella. Parietal wall covered by a thin 
callus. Length, 4.7; diameter, 1.2 mm. (Bartsch.) 
Type in United States National Museum, No. 250632. Type locality, 
off San Diego Bay, California. 
Range. Known only from type locality. 
Cerithiopsis diomedae Bartsch, 1911 
Proceedings of the United States National Museum, 40:359; PI. 37, fig. 5. 
Shell small, elongate-conic, brown. (Nuclear whorls decollated.) Post- 
nuclear whorls with a strongly channeled suture in which the posterior 
edge of the peripheral cord is apparent on all the whorls; marked by three 
spiral cords, of which the first is considerably weaker than the other two 
and is situated at the summit, rendering this somewhat shouldered; the 
third is about as far posterior to the suture as it is removed from the 
median, while the second is halfway between the first and third. The 
spaces between the spiral cords are equal and about one and one-half 
times as wide as the cords. In addition to the spiral sculpture, the whorls 
are marked by well-rounded, slender, protractive, axial ribs which are 
almost equal to the spiral cords in strength. Of these ribs, 16 occur upon 
the first, 18 upon the second to fourth, 20 upon the fifth and sixth, and 24 
upon the penultimate turn. The junctions of the axial ribs and spiral cords 
form moderately strong, rounded tubercles, while the spaces inclosed 
between them are rectangular pits having their long axes parallel with the 
spiral structure. Periphery of the last whorl marked by strong, spiral cord, 
which is separated from the supraperipheral cord by a channel as wide as 
that which separates the supraperipheral cord from the median and, like 
it, is crossed by the axial ribs which terminate at the posterior edge of the 
peripheral cord. Base very long, concave, marked by incremental lines and 
a single, obsolete fasciole a little posterior to the insertion of the columella. 
Aperture irregularly oval; posterior angle very obtuse; outer lip thin, 
showing the external sculpture within by transmitted light, rendered sinu¬ 
ous at the edge by the external sculpture; columella long, curved, and 
twisted, the edge reflected; parietal wall glazed with a thick callus. Length, 
4.3; diameter, 1.5 mm. (Bartsch.) 
Type in United States National Museum, No. 213302. Type locality, 
U.S. Bureau of Fisheries, Steamer “Albatross,” Station 3566, San Diego 
Bay, California. 
Range. San Diego Bay, California, to Todos Santos Bay, Lower Cali¬ 
fornia. 
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