32 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Aperture irregular, channeled anteriorly; posterior angle obtuse; outer lip 
rendered sinuous by the external sculpture; columella oblique, somewhat 
twisted; parietal wall glazed with a thin callus. Length, 7.5; diameter, 
2.8 mm. (Bartsch.) 
Type in United States National Museum, No. 165232. Pleistocene. 
Type locality, Pleistocene at Santa Barbara, California. 
Range. Catalina Island to San Diego; Pleistocene, Santa Barbara, 
California. 
Bittium catalinense inornatum Bartsch, 1911 
Plate 75, fig. 3 
Proceedings of the United States National Museum, 40:403; PI. 51, fig. 3. 
Shell similar to Bittium catalinense, but lacking the plain spiral keel in 
the suture. Length, 7.2; diameter, 2.3 mm. (Bartsch.) 
Type in United States National Museum, No. 195153. Type locality, 
Catalina Island, California. 
Range. Catalina Island, California. Also Pleistocene. 
Bittium ornatissimum Bartsch, 1911 
Plate 76, figs. 4, 5 
Proceedings of the United States National Museum , 40:403; PI. 51, figs. 4, 5. 
Shell elongate-conic, creamy white. Nuclear whorls one and one-half, 
marked by two slender threads which divide the space between the sutures 
into three equal parts. Post-nuclear whorls strongly shouldered at the 
summit, marked by three strong spiral keels which divide the space between 
the sutures into four equal parts. The space between the first of these 
keels below the summit and the summit is a little narrower than the rest. 
In addition to these three strong spiral keels, intercalated keels are present, 
the first of which is at the summit, while another occurs between each of 
the other keels. On the last whorl these attain a strength almost equal to 
that of the primary keels. In addition to this spiral sculpture, the whorls 
are marked by well-developed, slightly retractive, axial ribs, of which 14 
occur upon the first and second, 15 upon the third, 16 upon the fourth, 
18 upon the fifth and sixth, 20 upon the seventh, 22 upon the eighth, 28 
upon the ninth and tenth, and 34 upon the penultimate turn. The inter¬ 
sections of the axial ribs and spiral keels form strong cusps, which are 
suddenly truncated posteriorly and slope gently anteriorly, the spaces in¬ 
closed between them being small, rounded pits. Sutures channeled. 
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