158 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
cords between the sutures, the three posterior of which are nodulous on 
the early whorls; the fourth, or suprasutural one being smooth. On the 
last whorl the nodules are obsolete. Of these cords, the one at the summit 
is the weakest and the second below it the strongest. The spaces between 
the spiral keels are about half as wide as the keels and rather shallow. 
In addition to the spiral sculpture the whorls are marked by slender, almost 
axial riblets, which render the three posterior keels on the early whorls 
nodulose at their intersections. Of these riblets, about eighteen occur upon 
the second and twenty-two upon the third whorl. On the fourth, which 
is the penultimate, the grooves between the keels are crossed by slender 
axial threads. Sutures strongly constricted. Periphery of the last whorl 
marked by a narrow, deep sulcus. Base moderately long, well-rounded, 
marked by five spiral cords, which grow successively weaker between 
the periphery and the umbilical area. Grooves between the sutural cords 
equal, crossed by numerous, slender, axial threads, which cause the spaces 
between the threads and cords to appear as minute pits. Aperture moder¬ 
ately large, somewhat effuse anteriorly; posterior angle acute; outer lip 
thin, showing the external sculpture within; inner lip moderately long, 
strong, somewhat curved, and reflected over and adnate to the base, 
provided with a slender fold at its insertion; parietal wall covered with a 
thin callus. Length, 3; diameter, 1.5 mm. (Bartsch.) 
Type in United States National Museum, No. 21162. Type locality, 
San Diego, California. 
Range. Known only from type locality. 
Odostomia euglypta E. K. Jordan, 1921 
Proceedings of the United States National Museum, 58:2; PI. 1, fig. 1. 
Shell minute, thin but fairly solid, rather broad; nuclear whorls large, 
inflated, somewhat eroded, evidently with quite strong spiral sculpture; 
postnuclear whorls four, well-rounded; sutures quite prominent; spiral 
ridges between the sutures four, the lower one the strongest, crossed by 
numerous, fairly strong, axial ribs which become weaker as they approach 
the outer lip; junction of transverse ribs and spiral ridges marked by 
prominent, blunt, rounded nodules; base moderate, with seven flattish spiral 
bands, the upper ones the strongest, without any transverse ribs; aperture 
ovate, slightly produced below ; columella with a fairly sharp fold; margin 
of outer lip scalloped, showing the external sculpture within. Color gray. 
Length 2.1; breadth, 1.2 mm. (E. K. Jordan.) 
Type in United States National Museum, No. 334780. Type locality, 
Trinidad, California. 
Range. Known only from type locality. 
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