300 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
ate; the gill rows ambient. Length about 19; width, 10; height, 5 mm. 
(Dali.) 
Type in United States National Museum, No. 218736. Type locality, 
San Pedro, California. 
Range. Known only from type locality. 
Family MOPALIIDAE 
Genus MOPALIA Gray, 1847 
Shell regular; laminae lengthened; anterior valve with six or more 
slits, the others with a single slit; last valve sinuate behind; sinus narrow; 
mucro median, depressed; sutures indented; girdle wide, bristly, sometimes 
fissured behind, sometimes projecting anteriorly. (Tryon, Structural and 
Systematic Conchology .) 
Type. C . blainvillei , Brod. 
Distribution. Northern Pacific, Alaska, Japan, Lower California. 
Mopalia ciliata Sowerby, 1840 
Annals and Magazine of Natural History, new series, 4:289. Conchological Illustra¬ 
tions, fig. 79. Tryon and Pilsbry, Manual of Conchology, 14:303; PI. 64, 
figs. 64-73. 
Ch. testa depressa, dorso subrotundato, valvis subreniformibus, ad 
latera disjunctis; areis lateralibus oblique granoso-sulcatis; costa granulosa 
utrinque marginata; areis centralibus granoso-sulcatis, valva prima radia- 
tim costata; margine ciliato. Long., %; lat., l / 2 poll. 
The valves are flattish, with the edges arched and slightly beaked, and 
not united at the lateral extremities; central areas longitudinally grooved; 
a slightly raised granular rib separates the lateral from the central areas; 
these are obliquely grooved so as to meet the grooves of the central areas 
at acute angles on the rib; margin brown, covered with light brownish 
hairs; the colors are variegated, green, yellow, and black. (Sowerby.) 
Shell oblong, rather depressed, the dorsal ridge carinated (sometimes 
rounded), side-slopes straight or somewhat convex. Surface lusterless, 
finely sculptured, variously colored, usually either (1) typical coloring, 
verdigris green maculated with black or black-brown, the girdle yellow or 
(2) maculated with maroon and sometimes touched with rich chestnut on 
the ridge, or having some valves or parts of valves vivid scarlet, or scarlet 
mixed with olive and snow-white, or entirely white; or (3) light olive-buff 
with brownish girdle. Valves somewhat beaked, the lateral areas bounded 
by a riblet, rather coarsely granulated, with larger granules along the pos- 
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