146 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
the succeeding turns, in the first of which it is about one-fourth immersed. 
Post-nuclear whorls well-rounded with appressed summits, moderately 
constricted at the sutures, marked at irregular intervals by strong varices; 
axial ribs somewhat sinuous, low, well-rounded, weakening toward the 
summit; 16 upon the first, 18 upon the second to eighth, 24 upon the ninth 
and tenth, 26 upon the eleventh and twelfth, 28 upon the thirteenth and 
penultimate turn. Intercostal spaces as wide as the ribs, marked by nine, 
equally spaced, spiral lines, which pass up on the sides of the ribs, but do 
not cross their summits; space between the incised spiral lines is marked 
by exceedingly fine spiral striations. Periphery of last whorl well-rounded. 
Base short, well-rounded, marked by the feeble continuations of the axial 
ribs, and seven, well-incised, spiral striations. Aperture rhomboidal; pos¬ 
terior angle obtuse; outer lip thin, showing the external markings within; 
as well as four color bands, one of which is at the periphery, another 
midway between the periphery and summit, the third at the summit, the 
fourth on the middle of the base; in addition to these bands there are four 
strong spiral folds, two on the base and two on the lip, which show deeply 
within the aperture; columella slender, somewhat twisted and slightly 
revolute. Length, 16.5; diameter, 4 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 160147. Type locality, 
off Catalina Island, California. 
Range. Known only from type locality. 
Turbonilla pentalopha Dali and Bartsch, 1903 
Plate 56, figs. 3, 3a 
Memoirs of the California Academy of Sciences, 3:282; PI. 1, figs. 1, la. 
Shell elongate-conic, chocolate-brown. Nuclear whorls small, three, 
forming a depressed, helicoid spire, whose axis is at right angles to 
that of the succeeding turns, in the first of which it is about one-third 
immersed. Post-nuclear whorls rounded on the earlier and flattened on 
the later turns, marked by strong, rounded, somewhat flexuous, slightly 
retractive, axial ribs, which are scarcely at all expressed on the first, and 
of which there are eighteen upon the first and second, twenty upon the 
third and fourth, twenty-two upon the fifth, twenty-four upon the sixth, 
and twenty-eight upon the penultimate turn. Intercostal spaces as wide 
as the ribs, marked by six, equal and equally spaced, spiral series of pits 
which pass up on the sides of the ribs but do not cross them. Sutures 
well-impressed. Periphery and base of the last whorl well-rounded, 
marked by the continuations of the axial ribs and seven, equally spaced, 
spiral striations agreeing in strength with those on the spire. The first 
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