CLASS GASTROPODA 
239 
ribs, corrugated more or less by strong incremental rugosities, alternated 
in front and behind with a single feebler rib, on the sides there are two or 
three minor riblets between the major ribs; apex rather acute, somewhat 
anterior; marginal notch shallow, its groove distinct on the internal face 
of the shell; the number of major ribs in the type specimen is about twenty. 
Length, 20; apex behind the notch, 7; width, 13; height, 7.5 mm. (Dali.) 
Type in United States National Museum. Type locality, San Nicolas 
Island, California. 
Range. Known only from type locality. 
Hemitoma yatesii Dali, 1901 
Plate 85, figs. 1, 3 
Nautilus, 14:125. Proceedings of the United States National Museum, 24; PI. 38, 
figs. 1-3. 
Shell large, coarse, strong, whitish-gray, or pale olive-green on the 
fresher portions especially, a very narrow margin about the base; sculp¬ 
tured with strong, not dichotomous, radial ribs, of which about 20 are 
primary, between each two of which lie from one to four secondary 
riblets, most numerous at the sides of the shell; besides these there is a 
very strong anal fasciole, higher and stronger externally than any of the 
ribs, extending from the apex, and ending in front at a notch about 3.5 
mm. deep and rounded above and behind; the radiating sculpture is sharply 
and irregularly imbricated by the rude and profuse incremental sculpture, 
which is too close and irregular to form reticulation; apex small, pointed, 
not much elevated, situated three-fifths of the way from the front to the 
posterior margin; the fasciole descending from it swerves a little to the 
right of the median line of the shell; interior white, the extreme margin 
pale olive-green but almost linear; anal furrow deep, extending nearly to 
the apex, where it is lost in a very pale olive deposit of shelly matter; 
margins crenulated by the sculpture; muscular impressions strong, the 
two recurved scars unequal, the right one larger. Long, of shell, 51; lat., 
36; alt., 13 mm. (Dali.) 
Type in United States National Museum. Type locality, Monterey 
Bay, California. 
Range. Forrester Island, Alaska, to Monterey, California. 
Genus PUNCTURELLA Lowe, 1827 
Shell conical, elevated, with the apex recurved; perforation in front 
of the apex, with a raised border (septum) internally; surface cancellated. 
(Tryon, Structural and Systematic Conchology.) 
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