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 



Plate i8i 



Alaska to Lower California. 



% 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 



