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216 Thais canaliculata Duclos Channeled Dogwinkle Figure 48b, c Aleutian chain to Monterey, California. I inch in length, moderately globose, its spire higher than that of emar- ginata, but lower than that of lamellosa. Columella arched, flattened below. Characterized by about 14 to 16 low, flat-topped, closely spaced, spiral cords on the body whorl. Suture slightly channeled. Color white or orange- brown, often spirally banded. Moderately common on rocks and mussel beds. Do not confuse with lima from Alaska. Thais emarginata Deshayes Emarginate Dogwinkle Figure 48a Bering Sea to Mexico. I inch in length, with a rather short spire and with globose whorls. Aperture large. Columella strongly arched, and flattened and slightly con- cave below. Sculpturing variable, but characteristically with coarse spiral cords, usually alternatingly small and large. Cords often scaled or coarsely noduled. Exterior yellow-gray to rusty-brown, often with darker, narrow spiral bands. Interior and columella light- to chestnut-brown. Exceedingly common in many places along the coast where there are rocks. Thais lima Gmelin File Dogwinkle Figure 486 Alaska and Japan to northern California. I to 2 inches in length, very similar to ca7ialiculata, but with 17 to 20 round-topped spiral cords, often smooth, sometimes minutely fimbriated. Cords often alternate in size. Color whitish or orange-brown, rarely banded. Common intertidally. Compare with canaliculata. Genus Ocenebra Gray 1847 Tritonalia Fleming 1828 may also be used as a name for this genus, al- though Ocenebra would seem to be the wiser choice and will probably be the final choice. Ocinebra is a misspelling. Ocenebra interfossa Carpenter Carpenter's Dwarf Triton Figure 49a Alaska to Lower California. /4 to % inch in length, spire half the length of the shell; light-gray in color, delicately sculptured. 8 to 1 1 axial ribs on the body whorl crossed by about a dozen strong, microscopically scaled spiral cords. The surface is