16 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
of the shell; upper portion of whorls more or less angulated; aperture 
ovate, about the same length as the spire; outer lip thickened, internally 
white, with four prominent denticles; columellar lip somewhat excavated, 
incrusted, with a purplish stain showing through the enamel; canal closed, 
moderately recurved; surface covered with a slight yellowish epidermis 
and numerous revolving costae of a whitish hue, finely dotted with red¬ 
dish-brown, and the intercostal sulcations near the edge of the outer lip 
with linear markings of the same color (one specimen shows brownish 
blotches upon the middle of the body whorl.) This shell is also longitudi¬ 
nally nodosely ribbed, the ribs decreasing in prominence as the whorls 
enlarge. Length, .50; width, .25 in. (R. E. C. Stearns.) 
Type in United States National Museum. Type locality, San Diego, 
California. 
Range. Monterey, California, to San Geronimo Island, Lower Cali¬ 
fornia. 
Tritonalia gracillima obesa (Stearns MS.) Dali, 1919 
Proceedings of the United States National Museum, 56:333. 
Shell resembling 7. gracillima in most respects but notably wider. The 
coloration is yellowish, with brown flecks, especially on the prominences. 
1 he canal closed. 1 he aperture is bluish-white, with four strong denticles 
on the anterior two-thirds of the inner lip. Height of shell, 19; of aperture 
and canal, 8; diameter, 7.5 mm. (Dali.) 
Type in United States National Museum, No. 228722. Type locality, 
Laguna Beach, California. 
Range. Monterey, California, to Gulf of California. 
Tritonalia lurida Middendorff, 1849 
Beitrage su einer Malacologia Rossica, 150; PI. 4, figs. 4, 5. 
Testa minuta lurida, crassa; ovato-conica; anfractibus convexis, longi- 
tudine aequahter ac confertissime strio-costulatis; costulis rotundato- 
carinatis prominentibus, incrementi vestigiis imbricato-scabratis; columella 
crassa labioque et tota apertura lacteis, vernicosis; labro crenulato, ad 
marginem acuto, tenui, interiora versus mox incrassato, aperturam angus- 
doTfff™ 11110 ™ 111 (5 ad 6) SCrie denticula t°: canali subclauso. (Midden- 
D.e Rippenstreifen verlaufen ganz gleichmassig neben einander bis 
au den Ranal hinab; durch quer fiber dieselben hinlaufenden Zuwachs- 
amellen erhalten sie ein feilenartig rauhes Aeussere die dieselben von 
einander trennenden Furchen sind sehr schmal, weniger denn halb so breit 
als die Rippenstreifen selbst, schneiden jedoch tief ein und werden im 
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