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156 American Seashells
% to % inch in length, dirty whitish gray in color with an undertone
of reddish brown. About a dozen whorls. With wide, flat-topped, raised
spiral cords between which are depressed, squarish, spiral furrows half as
wide as the cords. 4 to 5 cords between sutures. Common below low
water. The subspecies montereyense Bartsch (Crescent City south to Lower
California) is glossy, whitish with brown maculations and is proportionately
shorter.
Bittium quadrifilatmn Carpenter Four-threaded Bittium
Monterey, Cahfornia, to Lower California.
% inch in length, similar to atteniiatum, but earliest whorls with about
a dozen smooth axial ribs which, however, in subsequent whorls become
beaded as 4 to 5 small spiral threads cross them. The sculpturing may become
faint at the very last third of the last whorl. Color reddish brown to gray.
A very common littoral species.
Bittium attenuatum Carpenter Slender Bittium
Forrester Island, Alaska, to Lower California.
/4 inch in length, slender, yellowish brown to dark-brown. Sculpture
variable. Nuclear whorls with two smooth spiral cords. Early whorls have
4 to 5 spiral rows of small beads, sometimes arranged axially. In the last
whorl, the cords gradually become smooth and flat-topped and resemble those
of eschrichti. Common just ofl^shore to 35 fathoms.
Subgenus Lirobitthmi Bartsch 191
Bittium interfossum Carpenter White Cancellate Bittium
Monterey, California, to Lower California.
/4 inch in length, pure-white; whorls in spire with 2 rows of sharp beads
connected by small axial and spiral threads or small cords. Base of shell with
3 very strong, rounded, smooth spiral cords. Moderately common under
rocks at low tide.
Subfamily LITIOPINAE
Genus Litiopa Rang 1829
Litiopa melanostojna Rang Brown Sargassum Snail
Pelagic in floating sargassum weed.
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