100 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
rounded, marked by seven equal and equally spaced, low, well-rounded, 
spiral cords, which are a little wider than the spaces that separate them. 
Aperture subcircular; posterior angle obtuse; outer lip strongly curved, 
rendered somewhat sinuous by the external sculpture; inner lip strongly 
curved; parietal wall covered by a thick callus which renders the peritreme 
complete. Length, 2.5; diameter, 1.2 mm. (Bartsch.) 
Type in United States National Museum, No. 271407. Type locality, 
Kyska Harbor, Aleutian Islands, Alaska. 
Range. Known only from type locality. 
Alvania almo Bartsch, 1911 
Plate 81, fig. 1 
Proceedings of the United States National Museum, 41:359; PI. 32, fig. 1. 
Shell minute, broadly ovate, yellowish-white. Nuclear whorls one and 
one-half, well-rounded, smooth. Post-nuclear whorls somewhat inflated, 
slopingly shouldered at the summit, marked by very slender, almost vertical, 
axial ribs, of which 18 occur upon the first, and 20 upon the penultimate 
turn. In addition to the axial sculpture, the whorls are marked between 
the sutures by two spiral cords equaling the ribs in strength. Of these, the 
first is a little posterior to the middle of the whorls, bounding the sloping 
shoulder, while the second is halfway between it and the suture. The 
intersections of the ribs and spiral cords form slender tubercles, while the 
spaces inclosed between them are well-impressed, squarish pits. The spaces 
inclosed between the first spiral cord and the summit and the axial ribs 
are rhomboidal areas, having their long axes parallel to the axial sculpture, 
while the spaces inclosed between the second spiral cord and the axial ribs 
and the suture are squarish pits. Suture moderately constricted. Periphery 
of the last whorl marked by a spiral sulcus, which is crossed by the 
continuations of the axial ribs. Base narrowly umbilicated, the umbilical 
chink being bounded by a tumid area, moderately long, well-rounded, 
slightly produced anteriorly, marked on the posterior half by two spiral 
cords equaling those between the sutures. Aperture almost circular; outer 
lip very thick all around, re-enforced by a strong varix; inner lip very 
stout, partly reflected over, and appressed to the base; parietal wall 
covered with a very thick callus which renders the peritreme complete. 
Length, 1.5; diameter, 1 mm. (Bartsch.) 
Type in United States National Museum, No. 23749a. Type locality, 
Santa Barbara Island, California. 
Range. Known only from type locality. 
[ 702 ] 
