CLASS GASTROPODA 
23 
prominence of nodes on the angle of the whorl; surface ornamented with 
numerous clear-cut, rather squarish, raised lines, and incremental lirulae 
in the interspaces; suture deeply appressed, wavy; aperture subpyriform; 
outer lip thickened, denticulated; inner lip incrusted, smooth; canal long, 
narrow, slightly curved; columella not perceptibly widened; umbilicus 
subperforate. Long., 33; lat., 17; body-whorl, 28; aperture including 
canal, 20; canal, 9 mm. (Arnold.) 
Type locality, Magdalena Bay, Lower California. 
Range. Monterey to San Diego, California. Fossil: Pleistocene— 
Santa Barbara, San Pedro, California. 
Tritonalia stearnsi Hemphill, 1911 
Transactions of the San Diego Society of Natural History, 7:100. 
The general outline of this small shell is diamond shaped, with the 
side points rounded off. It is composed of six turns or whorls. The 
nucleus or embryonic whorls are white, rather rough, and consist of 
about two turns. The next whorl has flat sides and a square-edged 
shoulder and is divided by a small revolving groove into two revolving 
nodulous riblets with shallow pits in the interstices. The antepenultimate 
and penultimate whorls are convex in form and divided into three re¬ 
volving nodulous riblets by two revolving grooves, with deep rounded 
pits in the interstices. The convex body-whorl comprises nearly two- 
thirds the entire length of the shell with similar sculpturing as that of 
the two preceding whorls* and with the pits more conspicuous above than 
below the periphery of the body-whorl. The suture is distinct and well- 
impressed. The outer lip is very much thickened for such a small shell, 
its outer edge being faintly denticulated by the revolving ribs and grooves, 
the inner edge just within the aperture bearing five denticles. The form 
of the aperture is oval, slightly pointed below; canal short and covered. 
The base of the columella is creased by an umbilical slit. The color is light 
or dark yellow or brownish, plain or with a single, white, revolving band 
at the periphery of the body-whorl, covering one and sometimes two of the 
revolving riblets. Length, 18; breadth, 8 mm. (Hemphill.) 
Type in Hemphill Collection, Stanford University, No. 375. Type 
locality, Monterey, California. 
Range. Known only from type locality. 
Tritonalia sclera Dali, 1919 
Proceedings of the United States National Museum, 56:334. 
Shell of moderate size, yellowish, flushed with more or less dark 
brown, with six well-rounded whorls exclusive of the (lost) nucleus; 
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