Page:American Seashells (1954).djvu/206

156 % 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 1 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 Plate 2ik Pelagic in floating sargassum weed.