90 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
wider than those occurring on the spire, crossed by the continuations of 
the axial ribs. Base moderately produced, slightly concave in the middle, 
marked by six, equal and almost equally spaced, spiral cords and the con¬ 
tinuations of the axial ribs. Aperture oblique, moderately large, oval; 
posterior angle acute; outer lip very thick, re-enforced immediately behind 
the edge by a strong varix, showing about 10 internal lirations within the 
aperture; inner lip very stout, curved, and reflected over and appressed to 
base; parietal wall covered with a thick callus which completes the peris¬ 
tome. Length, 3.3; diameter, 1.9 mm. (Bartsch.) 
Type in United States National Museum, No. 213684. Type locality, 
Monterey, California. 
Range. Known only from type locality. 
Alvania californica Bartsch, 1911 
Plate 80, fig. 9 
Proceedings of the United States National Museum, 41:340; PI. 29, fig. 9. 
Shell elongate-ovate, the spire posterior to the periphery of the last 
whorl forming a perfect cone, yellowish-white. Nuclear whorls two and 
one-half, well-rounded, smooth, separated by a moderately constricted 
suture. Post-nuclear whorls moderately well-rounded, marked by slender, 
rounded, slightly protractive, axial ribs, of which 26 occur upon the first 
and 34 upon the second and the penultimate turn. These axial ribs extend 
quite prominently from the summit of the whorls, where they form slender 
cusps, to the periphery of the whorls, becoming evanescent immediately 
anterior to the periphery. In addition to the axial ribs, the whorls are 
marked by spiral cords about as strong as the axial ribs. Of these two 
occur upon the first volution, where they divide the space between the 
sutures into three equal parts; on the second there are four, while upon 
the penultimate turn there are six. Suture strongly channeled. Periphery 
of the last whorl marked by a sulcus as wide as the one which separates 
the two cords posterior to it. Base moderately long, well-rounded, marked 
by six almost equally spaced, spiral cords, which grow successively stronger 
from the periphery to the umbilical area. In addition to these spiral cords, 
there are feeble extensions of the axial ribs occurring in the space between 
the first and second sulcus anterior to the periphery. Aperture very broadly 
oval; posterior angle obtuse; outer lip very thick, re-enforced immediately 
behind the edge by a strong varix, showing about 10 lirations within; 
inner lip stout, curved, strongly reflected over and appressed to the base; 
parietal wall covered with a thick callus, which completes the peristome. 
Length, 2.5; diameter, 1.4 mm. (Bartsch.) 
[6921 
