CLASS GASTROPODA 
99 
axial ribs on the first two turns are rectangular pits, having their long axes 
parallel with the axial sculpture. On the last whorl an additional spiral 
cord renders the pits between this cord and the next spiral cord and the 
axial ribs also squarish. Suture strongly constricted. Periphery of the last 
whorl marked by a sulcus as wide as that separating the suprasutural cord 
from the one adjacent to it anteriorly. Base well-rounded, strongly um- 
bilicated, marked by four equal and almost equally spaced spiral cords, 
which are as strong as those occurring between the sutures and the feeble 
continuations of the axial ribs. Aperture subcircular; outer lip thickened 
all around by a very thick varix; inner lip stout, decidedly curved, some¬ 
what reflected over and appressed to the base; parietal wall covered with 
a very thick callus, which renders the peritreme complete. Length, 1.6; 
diameter, 1.05 mm. (Bartsch.) 
Type in United States National Museum, No. 152193a. Type locality, 
San Pedro, California. 
Range. San Pedro, California, to South Coronado Island. 
Alvania kyskaensis Bartsch, 1917 
See Part II, Plate 67, fig. 6 
Proceedings of the United States National Museum, 52:677; PI. 46, fig. 6. 
Shell elongate-ovate, pale brownish-yellow. Nuclear whorls one and 
one-half, well-rounded, marked by very slender spiral striations and ex¬ 
ceedingly fine incremental lines. Post-nuclear whorls strongly rounded, 
weakly shouldered at the summit, marked by slender axial riblets which 
are somewhat sinuous and slightly retractively slanting. Of these ribs 24 
occur upon the first, 26 upon the second, and 40 upon the penultimate turn ; 
these are about one-third as wide as the spaces that separate them. In 
addition to the axial sculpture, the whorls are marked by four spiral cords, 
of which the first, which is about as far from the summit as it is distant 
from the second, is very weak on the first two whorls, but on the last 
assumes almost the strength of the three co*ds. The other three cords 
are of equal strength and spacing. The junction of the axial ribs and the 
spiral cords, which are a little stronger than the ribs, form weak nodules, 
while the spaces inclosed between them appear as well-impressed, squarish 
pits. In addition to this sculpture, the entire surface is marked by very 
fine incremental lines and numerous microscopic spiral striations, the two 
lending it a clothlike texture. Suture strongly constricted. On the last 
whorl the first basal keel makes its appearance above the summit of the 
succeeding turn. Periphery of the last whorl marked by a spiral sulcus, 
about as wide as those separating the cords on the spire. Base well- 
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