98 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
well-developed, somewhat sinuous, rounded, protractive axial ribs, of 
which there are about fourteen upon the third, sixteen upon the fourth 
and fifth, eighteen upon the eighth, twenty upon the ninth to eleventh, 
and twenty-two upon the twelfth and penultimate turns. Intercostal spaces 
almost equal to the ribs in width, shallow, terminating some little dis¬ 
tance posterior to the summit of the succeeding whorl, thus leaving a 
rather broad, plain band above the suture in each turn. Sutures strongly 
constricted. Periphery of the last whorl well-rounded. Base short, 
well-rounded. Entire surface of spire and base marked by very fine, 
closely spaced, spiral striations. Aperture subquadrate. Posterior angle 
obtuse, outer lip thin, showing the external markings within, columellar 
slender, well-curved and slightly revolute. Length, 8.3; diameter, 1.9 mm. 
(Dali and Bartsch.) 
Type in United States National Museum, No. 163244. Type locality, 
off Redondo, California. 
Range. Redondo to San Diego, California. 
Turbonilla bakeri Bartsch, 1912 
Proceedings of the United States National Museum, 42 :265; PI. 35, figs. 10, 10a. 
Shell elongate-conic, bluish-white. Nuclear whorls small, two and 
one-half, forming a quite elevated, helicoid spire, whose axis is at right 
angles to that of the succeeding turns, in the first of which it is about 
one-fifth immersed. Post-nuclear whorls slightly rounded, narrowly 
shouldered at the summit, somewhat constricted at the suture, marked 
by very regular, strong, rounded, slightly protractive, axial ribs, which 
become somewhat expanded at the summit. Of these ribs, fourteen 
occur upon the first four turns, sixteen upon the fifth to tenth, eighteen 
upon the eleventh, and twenty upon the penultimate turn. Intercostal 
spaces strongly impressed, almost as wide as the ribs, terminating shortly 
before reaching the suture, thus leaving a narrow plain band immediately 
above the suture. Sutures well-impressed. Periphery of the last whorl 
and short base well-rounded, smooth, except for fine incremental lines 
and the numerous, exceedingly fine, closely-spaced, wavy, spiral stria¬ 
tions which cover the entire surface of the shell. Aperture subquadrate; 
posterior angle obtuse; outer lip thin, showing the external sculpture 
within; inner lip almost straight, slightly revolute; parietal wall glazed 
with a thin callus. Length, 8; diameter, 1.8 mm. (Bartsch.) 
Type in United States National Museum, No. 211549. Type locality, 
San Diego Bay, California. 
Range. Known only from type locality. 
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