61 i) 
21:0873 Concholepas antiquatus L. is Hipponyx a. 
21:0874 Conus ravus Gld. is C. californicus. 
21:0875 Crepidula californica Nutt. is C. aculeata. 
21:0876 Crepidula explanata Gld. is navicelloides. 
21:0877 Crepidula nummaria Gld. is navicelloides. 
21:0878 Crepidula rostriformis Gld. is adunca. 
21:0879 Orepidula rugosa Nutt. is onyx, 
21:0880 Crucibulum dumosa Tuomey & Holmes, is spinosum. 
21:0881 Crypta adunca Sby. is Crepidula a. 
21:0882 Crypta dorsata Brod. is Crepidula d. 
21:0883 Cryptodon bisectus Conr,. is Thyasira b. 
21:0884 Cryptodon flexuosus Cpr. is (non Mont.) is Thyasira 
gouldi. 
21:0885 Cryptomya ovalis Conr. is C. californica. 
21:0886 Cumingia californica Conr. is lamellosa. 
21:0887 Cumingia similis A. Ad. is lamellosa. 
21:088 Genus Cuspidaria Nardo, 1840. 
Neaera, of former lists. 
21:0889 Cuspidaria apoderma Dall, 1916. 
Off Sitka, Alaska; Panama Bay, in deep water. 
21:0890 Cuspidaria balboae Dall, 1916. 
Cortez Bank, Cal., in 60 fathoms. 
21:0891 Cuspidaria beringensis Leche, 1883. 
Bering Sea; Panama Bay. 
21:0892 Ouspidaria californica Dall, 1886 sub Neaera. 
Puget Sound to San Diego, Cal. (2461). 
21:0893 Cuspidaria chilensis Dall, 1889. 
Off Oregon, 277 fms.; Chile, 1036 fms. 
21:0894 Cuspidaria glacialis G. O. Sars, 1878. 
Off San Diego, Cal., 239 fms.; Atlantic. 
21:0895 Ouspidaria pectinata Cpr., 1864, sub Neaera. 
Monterey, Cal., to Panama Bay. (359). 
21:0896 Cuspidaria planetica Dall, 1908. 
Bering Sea; Coronado Islands, in deep water. 
21:0897 Cyclas acutilineata Conr. is Lucina a. 
21:0898 Genus Cylichna Brown. 
Shell strong, cylindrical, smooth or punctate-striate; spire 
minute or truncated; aperture narrow, rounded in front; colum- 
ella callous, with 1 plait. 
21:0899 Oylichna alba Brown sub Volvaria. 
Shell 10.5 mm long, 4.25 in maximum diameter; smooth, 
spire truncate; aperture narrow posteriorly for about two-thirds 
length of shell, when inner lip gradually retracts to columella, 
forming a rounded anterior end to aperture. Monterey to San 
Diego, Cal. 
21:0900 Cylichna cylindracea Cnr. (non L.), is C; alba. 
21:0901 Cypricardia pedroana Conr. is Petricola denticulata. 
21:0902 Cyprina bisecta Conr. is Thyasira b. 
21:0903 Cytherea callosa Conr. is Amiantis c., 
21:0904 Cytherea crassatelloides Conr. is Tivela c. 
21:0905 Cytherea gigantea Sby. is Dosinia ponderosa. 
21:0906 Cytherea solidissima Phil, is Tivela stultorum. 
21:0907 Cytherea stultorum Gray, is Tivela s. 
21:0908 Genus Dacridium Torell, 1859. 
Hinge crenulations tuberculiform anteriorly, elongate pos- 
teriorly. Treated by Tyron as a subgenus of Crenella, by Dall 
as distinct. 
