Description. Shell broadly oval, but irregular in outline, moderately inflated; surface smooth or with undulating radial ribs; apex at posterior margin; coiled stage limited to early juvenile, deck with raised medial fold, attached at left side and posteriorly; color mottled brown and white. Length 12-25 mm.
Type Locality and Type Specimens. Santa Elena, Ecuador. Type material unknown. The species is better known by its junior synonym Crepidula lingulata Gould, described from Puget Sound, for which the holotype is USNM 5871. Material Examined. Santa Maria Basin, Phase I, sta. 6, 109 m (1); sta. 25, 390 m (1). Other material examined: 830 lots in LACM collection.
Distribution. Bering Sea, Alaska, to Bahia Independencia, Peru (14°S). Habitat. Abundant on rocky substrate from the intertidal zone to 20 m, less common in deeper water to 100 m. This is one of the most abundant of eastern Pacific gastropods.
Remarks. The name Crepipatella dorsata has previously been applied to forms occurring in the tropical eastern Pacific, whereas Crepipatella lingulata has been used for the northern forms, but there is no evidence that there is a distinction between a tropical and a more northern species. Hoagland (1977:373) placed the taxa C. dorsata and C. lingulata in synonymy, a course of action followed here.