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188 Americail Seash ells
smooth and narrowly channeled. Shell smooth, yellowish white and covered
with a thin, yellowish brown periostracum which flakes off when dry. Um-
bilicus absent or a very slight slit. Operculum paucispiral, horny, translucentbrown
and with microscopic, spiral lines. A moderately common, cold-water
species found just offshore down to 70 fathoms.
Its counterpart, A. purpurea Dall, common in Alaska, is very similar, but
% inch in length and with a greenish and darker periostracum.
Eunaticina oldroydi Dall
Oregon to San Diego, California.
Genus Eunaticina Fischer 1885
Oldroyd's Fragile Moon-slieli
Figure 4^^-
1/4 to iVi inches in length, resembling Lunatia leivisi, but much lighter
in weight, with a more pointed spire, without the heavy, brownish callus and
having, instead, the upper part of the columella expanded into a white, thin
area which partially obscures the umbilicus. Micro-sculpturing on shell exte-
rior is prominent. Moderately common; dredged offshore 30 to 70 fathoms.
Figure 43. a, Polifiices draconis Dall, 2 inches (Pacific Coast); b, Natica clausa
Bred, and Sby., i inch (Arctic waters); c, Jjiimtia pallida Bred, and Sby., 1^-2
inches (Arctic waters); d, Lamellaria diegoensis Dall, Y^ irich ( Califoi-nia); e,
Eunaticina oldroydi Dall, 2 inches (Pacific Coast).