284 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
about as wide as the spaces that separate them. The ribs and the intercostal 
spaces are marked by numerous, closely spaced spiral striations. Suture 
moderately constricted. Periphery of the last whorl inflated, well-rounded. 
Base short, somewhat inflated, well-rounded, marked by the feeble con¬ 
tinuations of the axial riblets, which evanesce shortly after passing the 
periphery, and numerous lines of growth and closely spaced spiral stria¬ 
tions. Aperture oval, posterior angle acute, outer lips thin, showing the 
external sculpture and the color markings within ; columella slightly curved, 
reflected over and appressed to the base for half of its length; parietal wall 
covered by a thin callus. 
Type in United States National Museum, No. 362145. Type locality, 
Shuyak Strait, Afognak Island, Alaska. It has lost the nucleus. The 10*4 
postnuclear whorls measure, length, 10.5 mm.; diameter, 2.7 mm. This is 
a member of the Turbonilla (Pyrgolampros) halia Dali and Bartsch group. 
It is not particularly closely related to any of the described species. 
Subgenus Pyrgiscus (see p. 123) 
Turbonilla delmontensis Bartsch, 1927 
Proceedings of the United States National Museum, 70:9; PI. 2, fig. 11. 
Shell elongate-conic, golden brown, with the incised spiral lines edged 
with red. Nuclear whorls decollated. Postnuclear whorls moderately 
rounded, narrowly shouldered at the summit, crossed by strong, slightly 
protractively slanting axial ribs, of which 14 occur upon the fourth and 
fifth of the remaining turns, 16 upon the sixth, 18 upon the seventh, 22 
upon the eighth, and 28 upon the last whorl, upon which they are somewhat 
enfeebled and less regularly developed and spaced. The intercostal spaces 
are about twice as wide as the ribs and are crossed by six equally spaced, 
incised spiral lines, of which the second is about three times as wide as the 
first, third, and fourth, while the fifth and sixth have about double the 
width of the narrow ones. Suture strongly constricted. Periphery of the 
last whorl well-rounded, somewhat inflated. Base short, moderately 
rounded, marked by somewhat irregularly spaced and irregularly devel¬ 
oped fine spiral lines, of which there are more than 15. The exact number 
cannot be determined on account of the erosion of the base. Aperture 
short, almost subquadrate; posterior angle obtuse; outer lip thin, showing 
the external sculpture within; inner lip almost vertical, reflected over and 
appressed to the base for almost half its length. 
Type in United States National Museum, No. 340818. Type locality, 
in 10 fathoms off Del Monte, California. It has nine post-nuclear whorls 
and measures, length, 9.7 mm.; diameter, 2.7 mm. This species is nearest 
related to Turbonilla (Pyrgiscus) auric oma Carpenter and Turbonilla 
(Pyrgiscus) castanea Keep. 
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