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216 American Seashells
Thais canaliculata Duclos Channeled Dogwinkle
Aleutian chain to Monterey, California.
Figure 48b, c
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
Bering Sea to Mexico.
Figure 48a
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
Alaska and Japan to northern California.
Figure 486
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
Alaska to Lower California.
Figure 49a
/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