CLASS GASTROPODA 
121 
Shell thin, white, circular, and perfectly flat, externally wrinkled by 
the loose stages of growth, and covered by a thick, yellowish epidermis. 
The apex is marginal and scarcely visible. The internal lamella is broader 
than long, arching, so as to enlarge the cavity, which would otherwise be 
almost nothing. Its edge is flexuous, retreating near the middle. Diameter, 
Y in. (Gould.) 
Type in United States National Museum. Type locality, Classet, Straits 
of Juan de Fuca. 
Range. Plover Bay, Bering Strait, to Mazatlan, Mexico. 
Crepidula fimbriata Reeve, 1859 
Conchologia I conic a, 11, fig. 11. 
Crep. testa oblique ovata, plana, apice lateraliter incurva, concentrice 
striata, versus marginem conspicue laminato-fimbriata, extus intusque 
pellucido-alba, ad latus livido-fusco uniradiata; appendice ad latus emargi- 
nato. (Reeve.) 
Shell obliquely ovate, flat, laterally incurved at the apex, concentrically 
striated, conspicuously laminarly frilled toward the margin, transparent- 
white without and within, stained with a livid-brown ray on one side; 
appendage notched at the side. (Reeve.) 
Type in British Museum? Type locality, Vancouver Strait. 
Range. Vancouver Island, British Columbia, to Gulf of California. 
Crepidula nivea C. B. Adams, 1852 
Plate 93, figs. 7, 9 
Catalogue of Shells Collected at Panama, 234. 
Shell ovate-elliptic: rather thick: within snow white: without dingy 
white, sometimes with a faint tinge of brown: very irregularly concen¬ 
trically more or less wrinkled, with very distinct striae of growth: apex 
turned more or less to the right, moderately prominent, marginal: septum 
longitudinally subangular, with a deep sinus at the left and a shallow one 
at the right: margin thick, exhibiting striae of growth. It closely resembles 
C. unguiformis, but constantly differs in character and station. (C. B. 
Adams.) 
Type in Amherst. Type locality, Panama. 
Range. Puget Sound to Panama. 
Crepidula nivea glottidiarum Dali, 1905 
Nautilus, 19:26. 
Shell uniformly straight, convex, smooth, equilateral, white and pos¬ 
teriorly attenuated. Living on Glottidia albida Hinds, and covering the 
