152 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
the periphery and those that bound the fifth cord are a little wider than 
the rest; the first and second below the summit and the second and 
third pit above the periphery are equal, and those between the third 
and fourth cords are also equal. Sutures well-impressed. Periphery 
of the last whorl inflated. Base well-rounded, marked by the feeble 
continuations of the axial ribs and eight, almost equal, incised, spiral lines. 
Aperture large, oval; posterior angle acute; outer lip somewhat flaring in 
the middle; columella slender, curved, and slightly revolute. Length, 10.2 ; 
diameter, 2.4 mm. (Dali and Bartsch.) 
Type in United States National Museum, No. 206890. Type locality, 
off Santa Catalina Island, California. 
Range. Known only from type locality. 
Subgenus Dunkeria Carpenter, 1856 
Turbonilla swani Dali and Bartsch, 1909 
Bulletin 68, United States National Museum, 129; Pi. 12, figs. 9, 9a. 
Shell elongate, pupoid, semi-transparent, light yellow. Nuclear whorls 
at least two, forming a low helicoid spire, whose axis is almost at right 
angles to that of the succeeding turns, in the first of which it is about 
one-half immersed. Post-nuclear whorls inflated, very strongly rounded, 
appressed at the summit, contracted at the periphery, marked by strong, 
decidedly-curved, lamellar, protractive axial ribs, of which eighteen 
occur upon all but the last whorl, the latter has twenty. Intercostal spaces 
twice as wide as the ribs, marked by fifteen, almost equal and almost 
equally spaced, spiral series of pits. Sutures constricted. Periphery and 
base of the last whorl well-rounded, the latter marked by the feeble con¬ 
tinuations of the axial ribs, and about twenty feeble, very wavy, incised 
spiral lines. Aperture oval; posterior angle acute; outer lip thin, showing 
the external sculpture within; columella slender, curved, with the posterior 
two-thirds re-enforced by the base. Length, 5; diameter, 1.5 mm. (Dali 
and Bartsch.) 
Type in United States National Museum, No. 160485. Type locality, 
San Pedro, California. 
Range. Known only from type locality. 
Genus ODOSTOMIA Fleming, 1817 1 
Shell with a sinistral apex, usually short, few-whorled, subconic or 
ovate, with a single columella fold, which varies in strength and sometimes 
i - - 
1 For descriptions of new species, received while this volume was in press, see 
Appendix, pp. 286-292. 
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