102 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
strongly rounded, smooth. Post-nuclear whorls strongly rounded, almost 
appressed at the summit and moderately constricted at the suture, marked 
by seven very low, flattened, spiral cords between the sutures, which are 
separated by a shallow impressed line. The axial sculpture consists of 
numerous very slender threads which are almost vertical. Suture strongly 
constricted. Periphery of the last whorl somewhat inflated, well-rounded, 
base moderately long, slightly attenuated anteriorly, marked by six low, 
ill-defined, rounded spiral cords, which, like those on the spire, are sepa¬ 
rated by mere impressed lines. The axial ribs also continue over the base. 
Aperture broadly oval, decidedly effuse at the junction of the basal and 
the outer lip; posterior angle obtuse; outer lip thick within, thin at the 
edge, evenly curved from the posterior angle to its junction with the inner 
lip; inner lip decidedly curved, somewhat reflected, and appressed to the 
base; parietal wall covered by a thick callus, which practically renders the 
peritreme complete. Length, 2; diameter, 1 mm. (Bartsch.) 
Type in United States National Museum, No. 268730. Type locality, 
Forrester Island, Alaska. 
Range. Known only from type locality. 
Alvania burrardensis Bartsch, 1921 
Proceedings of the Biological Society of Washington, 34: 38. 
Shell very broadly ovate, pale yellow. Nuclear whorls decollated in all 
our specimens. Postnuclear whorls strongly inflated, marked by strong, 
rather distantly spaced, curved, and slightly protractively slanting axial 
ribs, of which twenty-four occur upon the next to the last and twenty-two 
upon the last turn. In addition to the axial ribs, the whorls are crossed by 
six equal, and equally spaced, broad spiral cords which render the axial 
ribs obscurely nodulose at their junction. The spaces separating the spiral 
cords are a little less wide than the cords. Periphery of the last whorl 
marked by a sulcus, which is crossed by the continuation of the axial ribs 
which extend partly over the base, but evanesce soon after passing the 
periphery. Base short, strongly rounded, marked by nine equal and equally 
spaced prominent spiral cords, which are a little wider than the spaces that 
separate them. Aperture subcircular; posterior angle obtuse; outer lip 
reinforced by a callus at the edge; inner lip curved and appressed at the 
base; parietal wall covered by a m'oderately thick callus. Length, 2.2; 
diameter, 2 mm. (Bartsch.) 
Type in United States National Museum, No. 340938. Type locality, 
Burred Inlet, British Columbia. 
Range. Known only from type locality. 
1704] 
