126 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
upper row of pits and the summit. Sutures well-impressed. Periphery 
of the last whorl well-rounded. Base short, well-rounded, marked by 
several well-incised spiral striations. Aperture subquadrate; posterior 
angle obtuse; outer lip thin, strongly bent at its anterior margin; colu¬ 
mella short, twisted, and slightly revolute. Length, 4.7; diameter, 1.4 mm. 
(Dali and Bartsch.) 
Type in United States National Museum, No. 205936. Type locality, 
San Diego, California. 
Range. Known only from type locality. 
Turbonilla pluto Dali and Bartsch, 1909 
Plate 53, fig. 9 
Bulletin 68, United States National Museum, 81; PI. 9, fig. 9. 
Shell very robust, chestnut-brown. (Nuclear whorls decollated.) 
Post-nuclear whorls flattened, moderately shouldered at the summit and 
scarcely at all contracted at the sutures, marked by rather irregular, low, 
rounded, variously slanting axial ribs, which are completely eroded on 
the first four whorls; on the fifth and sixth there are twenty-four, on 
the seventh and the penultimate there are thirty-eight. Intercostal spaces 
a little narrower than the ribs, marked by four spiral series of broad, 
strongly impressed, spiral pits, on the anterior two-thirds of the whorls 
between the sutures; the posterior third is marked by two closely spaced, 
well-incised, strong spiral lines, the first of which is about as far posterior 
to the neighboring pit as the space which separates that from its fellow. 
Both spiral pits and lines cut strongly into the sides of the ribs and pass 
feebly over their summits, rendering them somewhat tuberculate. Sutures 
well-impressed. Periphery of the last whorl marked by a plain band, 
well-rounded. Base moderately long, well-rounded, marked by very 
feeble continuations of the axial ribs and six, equal and equally spaced, 
broad, and deeply incised spiral lines. Aperture pear-shaped; posterior 
angle acute; outer lip rather thick; columella short, oblique, and some¬ 
what revolute. Length, 7.4; diameter, 2.3 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 206866. Type locality, 
off San Pedro, California, in 10 fathoms. 
Range. Known only from type locality. 
Turbonilla jewetti Dali and Bartsch, 1909 
Plate 55, figs. 2, 2 a 
Bulletin 68, United States National Museum, 82; PI. 7, figs. 2, 2a. 
Shell short, robust, rose-pink, wax-yellow at tip. Nuclear whorls two 
and one-half, very small, low, helicoid, having their axis at right angles 
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