120 MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Crepidula aculeata Gmelin, 1792 
Systema Naturae, 7:3693. Tryon, Manual of Conchology, 8:129; PI. 39, figs. 61-65. 
Oval moderately convex, apex lateral, spiral, surface covered with 
radiating prickly or spinose ridges; whitish, yellowish or brownish, often 
chest-rayed, interior often splotched or rayed with chocolate, septum white. 
Length 1-1.5 inches. (Tryon, Manual of Conchology.) 
Type in ? Type locality, not known to writer. 
Range. Santa Barbara, California, to Valparaiso, Chile. 
Subgenus Crepipatella Lesson, 1830 
Crepidula lingulata Gould, 1846 
Plate 93, fig. 8 
Testa parva, depressa, obliqua, rotundata, alba, lineis numerosis crebre 
divaricantibus radiata, epidermide pallido induta; apice acuto, libero, prope 
marginem sito: intus lutescens; septo linguiformi, excavato, ad medium 
carina diviso et oblique protruso, ad latus sinistrum prof unde sinuato. 
Shell small, depressed, thick at the centre, but flattened and thinning 
towards the margin, rounded at base, the apex free, acute, slightly curving 
to the right, the surface near the margin furrowed with numerous, delicate, 
radiating lines, which branch very frequently, and covered with a very 
delicate, pale, fugacious epidermis. Interior pale brownish-yellow, with a 
broadly expanded flat margin. The septum is small, white, excavated; 
divided by a delicate ridge, deeply detached from the left side, and at the 
middle projecting far and obliquely. Diameter, j/g inch; altitude, inch. 
(Gould.) 
Type in United States National Museum? Type locality, Puget Sound, 
Washington. 
Range. Bering Sea to Panama. 
Subgenus Ianacus Morch, 1852 
Crepidula nummaria Gould, 1846 
Plate 91, figs. 14, 14a, 14 b 
Proceedings of the Boston Society of Natural History, 2:160. Mollusca and Shells 
of the United States Exploring Expedition, 377, figs. 480, a, b. 
Testa tenui, explanata, circularis, alba, striis incrementalibus laxis 
insculpta, epidermide flavo-cornea induta; apice vix conspicuo, marginali: 
septum internum latius quam longum, deorsum fornicatum; margine 
flexuoso: cavositas fere nulli. 
f 7221 
