CLASS GASTROPODA 
267 
whorls, the thirteen remaining whorls measuring: Length, 6.9; diameter, 
1.8 mm. (Bartsch.) 
Type in United States National Museum, No. 195200. Type locality, 
eight miles off Point Loma Light, California, U. S. Bureau of Fisheries, 
Station 4310. 
Range. San Pedro to San Diego, California. 
Cerithiopsis alcima Bartsch, 1911 
Plate 69, fig. 2 
Proceedings of the United States National Museum, 40:350; PI. 39, fig. 2. 
Shell elongate-conic, chestnut brown. Nuclear whorls three and one- 
half, small, moderately rounded, separated by a well-impressed suture; the 
first whorl smooth; the second and third marked by slender, protractive, 
curved, axial ribs, of which 18 occur upon the second and 20 upon the 
third. Intercostal spaces about twice as wide as the axial ribs, crossed by 
about 15 slender, spiral lirations. Post-nuclear whorls moderately rounded, 
appressed at the summit, ornamented with three spiral cords, of which the 
first is at the summit, which on the first five whorls is scarcely apparent; 
beginning with the sixth turn, it increases in size until on the last volution 
it almost equals the other two. The third cord is about as far posterior to 
the suture as it is from the second cord, which is halfway between the first 
and third. The spiral cords are not quite as wide as the spaces that sepa¬ 
rate them. In addition to the spiral cords, the whorls are marked by low, 
almost vertical, axial ribs, which are less strong than the spiral cords and 
render their intersections with these cuspidate. Of the axial ribs, 16 occur 
upon the second to fourth, 18 upon the fifth and sixth, 20 upon the seventh, 
22 upon the eighth, and 24 upon the ninth and penultimate turn. The 
tubercles formed by the junction of the first cord and the axial ribs are 
well-rounded; those formed by the junction of the median cord and the 
ribs are truncated anteriorly and posteriorly, sloping a little more gently 
anteriorly than posteriorly; those formed by the junction of the third cord 
and the ribs are decidedly truncated posteriorly, sloping gently anteriorly. 
The spaces inclosed between the axial ribs and the spiral cords are strongly 
impressed squarish pits. Suture well-marked, showing the posterior edge 
of the peripheral cord. Periphery of the last whorl marked by a strong 
cord, separated from the supraperipheral cord by a sulcus almost as wide 
as that which separated the supraperipheral cord from the median, and 
like it, crossed by the continuations of the axial ribs which terminate at 
the posterior border of the peripheral cord. Base rather short, concave, 
marked by two, strong, spiral cords and a slender fasciole, the latter sur- 
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