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 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. 



