282 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
rounded axial ribs, which are closely spaced on the early whorls, rather 
distantly on the middle whorls, and again closely placed on the last turn, 
where they become somewhat enfeebled. Of these ribs, which are almost 
vertical, 22 occur upon the first of the remaining turns, 24 upon the 
second to sixth, 26 upon the seventh, and 30 upon the last. The spaces 
between the ribs are strongly impressed and almost as wide as the ribs on 
the first two turns. On the next four they are decidedly wider than the 
ribs, while on the next to the last they again equal the ribs and on the last 
they are narrower. The entire surface of the spire is marked, in addition, 
by fine spiral striations. Periphery of the last whorl well-rounded. Base 
moderately long, well-rounded, marked by the feeble continuations of the 
axial ribs and the fine microscopic spiral striations. Aperture oval; pos¬ 
terior angle acute; outer lip thin; inner lip somewhat sinuous, reflected 
over, but not appressed to the base; parietal wall covered by a thick callus. 
Type in United States National Museum, No. 340819. Type locality, 
San Pedro, California. Length, 12.5 mm.; diameter, 4 mm. This is the 
largest of the known West American Pyrgolantpros. 
Turbonilla shuyakensis Bartsch, 1927 
Proceedings of the United States National Museum, 70: 7; PI. 2, fig. 1. 
Shell broadly conic, stout, flesh-colored, with a broad band of chestnut 
brown encircling the periphery. This band extends almost as far anterior 
to the periphery as it does upon the base. Nuclear whorls decollated. 
Postnuclear whorls rather inflated, appressed at the summit, slightly 
rounded near the summit and the periphery and somewhat flattened in the 
middle, marked by very strong, slightly protractively curved, rounded 
axial ribs, of which 16 occur upon the first four of the remaining turns, 
and 18 upon the rest. The intercostal spaces, which are about as broad as 
the ribs, are deeply impressed. In addition to the strong axial ribs, the 
whorls are marked by fine incremental lines which are apparent in both 
intercostal spaces and on the ribs; they are also marked by rather strong, 
closely spaced spiral striations. Suture strongly impressed, constricting 
the whorls. Periphery angulated. Base short, slightly inflated, well- 
rounded, marked by the very feeble continuations of the axial ribs, which 
evanesce shortly after passing the periphery, numerous lines of growth, 
and closely spaced, strong spiral striations. Aperture rather large, broadly 
oval, posterior angle obtuse; outer lip thin, showing the external markings 
as well as the color bands within; columella slender, slightly curved, and 
slightly reflected over the base to which it is appressed for the posterior 
half of its length. 
Type in United States National Museum, No. 362144. Type locality, 
[ 580 ] 
