APPENDIX 
287 
half the nuclear spire projects. Postnuclear whorls marked by rather 
strong, retractively slanting, axial ribs which are a little broader than the 
spaces that separate them. Of these ribs 14 occur upon the first, 16 upon 
the second to fourth, 18 upon the fifth and last turns. In addition to this 
the whorls are marked by four spiral cords which render the junction with 
the axial ribs tuberculated. The tubercules are rounded on the middle 
whorls and slightly elongated on the last turn, the elongation corresponding 
with the spiral sculpture. The spaces inclosed between the axial ribs and 
the spiral cords are deeply impressed, rounded pits. Suture strongly con¬ 
stricted, channeled. Periphery of the last whorl marked by a rather broad 
channel. Base rather long, marked by eight spiral cords of which the first 
two, near the periphery, are much stronger than the rest, the others becom¬ 
ing successively weaker. In addition to this the deep channels between 
the spiral cords are crossed by numerous slender axial threads which give 
them a finely ribbed appearance. Aperture elongate-oval; decidedly angu- 
lated anteriorly; posterior angle acute; outer lip thin, showing the external 
sculpture within, and sinuous at the edge; columella twisted, provided with 
a rather oblique fold a little anterior to its insertion; parietal wall covered 
by a rather thick callus. 
Type in United States National Museum, No. 362446. Type locality, 
San Clemente Island, California. It has six and one-half postnuclear 
whorls and measures, length, 3.7 mm.; diameter, 1.2 mm. 
Odostomia clementensis Bartsch, 1927 
Proceedings of the United States National Museum, 70: 15; PI. 3, fig. 2. 
Shell very broadly conic, bluish white. Nuclear whorls decollated. 
Postnuclear whorls increasing rapidly in size, marked by poorly developed 
axial ribs which are strongest near the summit, but evanesce before reach¬ 
ing the periphery. Of these 20 occur upon all the whorls. These ribs are 
a little wider than the spaces that separate them. In addition to these ribs 
the whorls are marked by five spiral cords between the summit and 
periphery, of which the first three are narrow and of about equal width 
and occupy the posterior half of the turns. These render the axial ribs 
tuberculate, the tubercles being elongate, the elongation corresponding with 
the spiral sculpture. The anterior two spiral cords are much broader. The 
posterior of these is feebly tuberculate, while the anterior is smooth. The 
spaces separating the spiral cords on the spire are of the same width, and 
the spaces inclosed between the axial ribs and spiral cords are narrow 
elongated pits, the long axes of which coincide with the spiral sculpture. 
These spiral pits pass up on the sides of the ribs and usually cross them. 
The first supraperipheral incised spiral line not being interrupted by ribs 
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