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126 American Seashells
Va inch in length, equally wide, very thick-shelled, resembling in shape
a Margarites. Pure white in color. Whorls rounded, 5 to 6 in number, each
bearing 5 to 6 strong, rounded, spiral cords, the lower 2 being below the
periphery of the whorl. Aperture and parietal wall glossy, slightly opalescent.
Columella arched, with a small tooth in the middle and a smaller one usually
at the base. No umbilicus. Commonly dredged from 35 to 450 fathoms.
H. linnei Dall from southeast Florida to Barbados has 8 smaller, beaded
spiral cords on the upper part of the whorls and 10 on the base, otherwise
it is very similar to albida. It is quite rare.
Homalopoma carpenteri Pilsbry Carpenter's Dwarf Turban
Alaska to Lower California.
Plate i8i
% to % inch (5 to 9 mm.) in length, solid, globose. Pinkish red to
brownish red in color. Last whorl and base with 15 to 20, evenly sized,
smooth, spiral cords separated from each other by a space about half as wide
as the cords. Base of pearly columella with 2 or 3 exceedingly weak nodules.
A very common species frequently washed ashore and inhabited by small
hermit crabs from Monterey to Mexico. Do not confuse with lurida.
Homalopoma lurida Dall Dark Dwarf Turban
Puget Sound to Lower California.
% inch (5 to 7 mm.) in length, similar to carpenteri, but half as large,
black-brown in color, although occasionally whitish with red axial streaks.
The spiral cords are usually fewer in number and more rounded. Moderately
common in shallow water under rocks.
Homalopoma bacula Carpenter Berry Dwarf Turban
Puget Sound to Lower California.
% inch or less in length, similar to carpenteri but with a flatter spire,
and smoothish, except for numerous incised, spiral lines producing very weak
threads. Color dark, rosy-brown. A moderately common shallow-water
species, sometimes found with carpe?iteri. A thorough anatomical and life
history study of this genus is needed to ascertain the validity of these species.
Fa7mly PHASIANELLIDAE
Genus Tricolia Risso 1826
Tricolia affinis C. B. Adams Checkered Pheasant