CLASS GASTROPODA 
103 
Turbonilla humerosa Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 52; PI. 3, figs. 10, 10a. 
Shell elongate-conic, milk-white. Nuclear whorls very small, two and 
one-half, depressed, helicoid, having their axis at right angles to that 
of the succeeding turns, in the first of which they are about one-fourth 
immersed. Post-nuclear whorls very strongly rounded moderately shoul¬ 
dered at the summit, marked by many strong lamellar, protractive axial 
ribs, which slope suddenly from a point about one-third of the distance 
between the sutures, anterior to the summit, giving the whorls a shoul¬ 
dered appearance at this place. Of these ribs, fourteen occur upon the 
second to fourth, sixteen upon the fifth to ninth, eighteen upon the 
tenth, and twenty upon the penultimate turn. Intercostal spaces deeply 
impressed, double the width of the ribs. Sutures strongly marked. Pe¬ 
riphery of the last whorl well-rounded. Base short, well-rounded. Entire 
surface of spire and base marked by many fine, wavy, spiral striations. 
Aperture subquadrate, posterior angle obtuse. Outer lip rather thick and 
somewhat revolute. Length, 6; diameter, 17 mm. (Dali and Bartsch,) 
Type in United States National Museum, No. 206857. Type locality, 
off Catalina Island, California. 
Range. Catalina Island to San Diego, California. 
Turbonilla galianoi Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 51; PI. 4, figs. 12, 12a. 
Shell elongate-conic, milk-white shining. Nuclear whorls very small, 
two and one-half, forming a rather elevated spire, having their axis at 
right angles to that of the succeeding turns, in the first of which they 
are about one-fourth immersed. Post-nuclear whorls well-rounded, very 
strongly tabulately shouldered at the summit, ornamented with well- 
developed, rounded, slightly protractively curved axial ribs. Of these 
ribs sixteen occur upon the first, second, and third, eighteen upon the 
fourth and fifth, twenty upon the sixth, twenty-two upon the seventh, 
twenty-four upon the eighth, twenty-six upon the ninth, and twenty-eight 
upon the penultimate turn. These ribs extend equally strong from the 
summit to the periphery of the whorls. Intercostal spaces not quite as 
wide as the ribs, well-impressed, extending anteriorly to the suture. 
Sutures strongly constricted. Periphery of the last whorl well-rounded. 
Base rather long, well-rounded. Entire surface of the spire and base 
marked by exceedingly fine spiral striations. Aperture subquadrate, pos¬ 
terior angle obtuse; outer lip thin, showing the external sculpture within; 
columella almost straight, slightly revolute. Length, 6.1; diameter, 1.8 mm. 
(Dali and Bartsch.) 
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