CLASS GASTROPODA 
127 
to that of the succeeding turns, in the first of which they are about one- 
third immersed. Post-nuclear whorls flattened, shouldered at the summit, 
marked by strong, rounded, slightly protractive axial ribs; of which 
eighteen occur upon the second, twenty upon the third, twenty-two upon 
the fourth and fifth, twenty-four upon the sixth, and twenty-six upon the 
penultimate turn. Intercostal spaces about equal to the ribs, strongly 
impressed, marked by five series of equal and equally spaced spiral pits, 
the first of which is at the periphery, the last a little farther from the 
summit than its neighbor. Sutures strongly marked, rendered sinuous by 
the ribs. Periphery of the last whorl rounded, marked by the feeble 
continuations of the axial ribs. Base moderately long, well-rounded, 
marked by eight, unequal and unequally spaced, spiral striations, the two 
immediately below the periphery being stronger than the rest and some¬ 
what interrupted. Aperture oval; outer lip thick within, columella stout, 
somewhat twisted and slightly revolute. Length, 5.5; diameter, 1.9 mm. 
(Dali and Bartsch.) 
Type in United States National Museum, No. 153048. Type locality, 
San Diego, California. 
Range. San Pedro, California, to San Hipolito Point, Lower Cali¬ 
fornia. 
Turbonilla dora Bartsch, 1917 
Proceedings of the United States National Museum, 52:649; PI. 42, fig. 10. 
Shell very large, elongate-conic, uniformly pale brown. Nuclear 
whorls decollated. Postnuclear whorls well-rounded, strongly appressed 
at the summit, marked on the early whorls by rather strong, almost ver¬ 
tical, axial ribs, which become evanescent on the later turns. Of these 
ribs eighteen occur upon the first to fourth, twenty upon the fifth, twenty- 
two upon the sixth, twenty-four upon the seventh, twenty-six upon the 
eighth, thirty-two upon the ninth, and thirty-four upon the tenth, while 
upon the penultimate whorl they become too enfeebled to be counted. 
The spiral sculpture consists of broad pits and feebly incised lines, the 
posterior fifth between the sutures being marked by six very fine, sub- 
equally spaced, spiral striations. These are followed by two stronger lines, 
which are succeeded by two strongly impressed pits; these are followed 
by a pit about half as wide as the last two, then by one a little stronger 
and finer, then by the widest pit of all, which is succeeded by one not 
quite as broad. These incised spiral lines pass upon and even cross the 
summit of the enfeebled ribs. Suture moderately constricted. Periphery 
of the last whorl decidedly inflated. Base moderately long, somewhat 
inflated, well-rounded, marked by about twenty-five, somewhat wavy, 
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