68 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Distribution. Universal. Arctic seas, Britain. Fossil. Silurian? 
Lias—United States, Europe, Thibet, South India. 
Modiolus modiolus Linnaeus, 1758. 
Syst. Nat. ed. 10, p. 706; Conch. Iconica, Modiola, pi. 1, fig. 2. 
M. testa laevi margine dorsali dilatato, natibus gibbis, cardine sub- 
laterali. (Linnaeus.) 
Shell oblong, somewhat trapeziform, ventricose toward the umbones, 
smooth or obsoletely wrinkle-striated; dark chestnut. (Conch. Iconica.) 
Type in British Museum? Type locality, Mediterranean. 
Range. Arctic to San Pedro, California, and Circumboreal. 
Modiolus rectus Conrad, 1837. 
Jour. Acad. Nat Sci. Phila 7:243; pi. 19, fig. 1. 
Shell produced, smooth, thin; anterior margin elevated; posterior side 
cuneiform; color brown, with a broad pale stripe extending from the 
beak toward the posterior margin; within very glossy and iridescent. 
Length, 2 inches. (Conrad.) 
Type in Phila. Acad. Nat. Sci.? Type locality, near Santa Barbara, 
California. 
Range. Bolinas Bay, California, to Magdalena Bay, Lower California. 
In the Pliocene, Santa Rosa; Twelve Mile House, San Mateo County; 
Soquel, Santa Cruz County; San Fernando; San Diego Well; San Diego. 
Miocene, El Toro Ranch, Monterey County; Foxen’s, Santa Barbara 
County. 
Modiolus flabellatus Gould, 1850. 
Plate 6, fig. 2. 
Boston Jour. Nat. Hist., 3:346. Rep. U. S. Expl. Exp. Moll.; fig. 11. 
Shell large, elongated, trapezoidal, dilated posteriorly; beaks elevated, 
pyramidal, contiguous, acute, placed at the anterior seventh; umbonal 
ridge elevated, angular above, widening and becoming more rounded 
backward; portion anterior to the slope trigonal, wedge-shaped in three 
directions; extremity narrow, rounding upward; dorsal and ventral mar¬ 
gins diverging, rectilinear for three-fourths of length, when the upper 
margin rounds downward; posterior extremity broadly rounded; epidermis 
glossy, first triangular third of a scorched, dark-chestnut brown or tan 
colour, palest at extremity; posterior third pale yellowish-corn colour; 
behind the umbonal ridge rigid with a coating of loose fringe-like termina¬ 
tions of the layers of growth; interior pearly white; slightly gaping in 
front. Length, 50; height, 100; diameter, 35 mm. (Gould.) 
Type in Boston Nat. Hist. Soc. ? Type locality, Puget Sound. 
Range. Vancouver Island to San Diego, California. 
