140 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
whorls they are less regular in size and spacing than on the preceding. 
Intercostal spaces about twice as wide as the ribs on the first seven whorls, 
averaging a little less in width upon the remaining; the intercostal spaces 
are strongly impressed, and marked with six strongly impressed series of 
spirally spaced pits, the first one below the summit being a little further 
from the summit than from its neighbor; between these spiral pits occur 
finer incised lines, of which there are 10 between the summit and the first 
strong pit, one each between the first and second, and second and third, 
two between the third and fourth, three between the fourth and fifth, and 
two between the fifth and sixth; the strong incised lines pass up on the 
sides of the ribs, constricting the ribs where they meet them; the fine lines 
are not apparent upon the ribs. Sutures strongly constricted. Periphery 
of the last whorl well-rounded. Base short, well-rounded, marked by 
about 20, very slender, incised, spiral lines. Aperture oval; posterior angle 
obtuse; outer lip thin, showing the external sculpture within; inner lip 
slightly curved, oblique, reflected, but not adnate to the base; parietal wall 
covered with a thin callus. Length, 11; diameter, 2.7 mm. (Bartsch.) 
Type in United States National Museum, No. 229011. Type locality, 
off San Diego, California. 
Range. Known only from type locality. 
Turbonilla eucosmobasis Dali and Bartsch, 1907 
Plate 54, figs. 8, 8o 
Proceedings of the United States National Museum, 33:507; PI. 45, figs. 8, 8a. 
Shell quite large, of very regular outline, creamy white. Nucleus rather 
small, composed of two and one-half whorls, helicoid with much depressed 
spire, somewhat obliquely about one-third immersed in the first of the 
succeeding turns, the axis of the nuclear spire being almost at a right angle 
to the axis of the later whorls. Post-nuclear whorls moderately rounded, 
widest a little above the suture, sloping gently toward the summit and more 
abruptly toward the base, ornamented by moderately strong, rounded, 
somewhat flexuous, axial ribs, of which about 18 appear upon the second, 
20 upon the seventh, 22 upon the eighth, and 27 upon the penultimate 
whorl. Intercostal spaces only moderately deep, a little wider than the 
ribs, marked by six, strong, incised, spiral lines, which extend up on the 
sides of the ribs and frequently pass over their summits; the uppermost or 
posterior one of these incised lines is least pronounced, the second one 
above the suture, and the third one about half again as far apart as the re¬ 
maining, which are equally spaced. In addition to these the shell is marked 
by many faint wavy spiral striations between the deep ones. Sutures plain, 
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