234 GUNDLACHIA. 
shining and purplish, the plate white towards 
the edge, and in some specimens showing a 
thickened, white semicircle continuous with 
its margin across the arch of the shell. 
Length 4, width 2, alt. 1-5 mill. 
California. 
2. GUNDLACHIA MEEKIANA, Stimpson. 
Plate 2, figs. 22-24. 
Full grown shell in general form ovate, 
aperture less ovate than in G. Californica. 
Dorsal part black, opaque, thick, apex very 
obtuse and inclined to the right. Lower part 
of the shell thin, translucent, whitish or very 
pale horn-color; more expanded to the left 
than to the right, the dorsum and left slope 
being strongly convex, while the right slope is 
nearly straight. 
District of Columbia. 
Mr. Stimpson ventures to suggest that the 
Gundlachia commences its life as an Ancylus, 
the dorsal opaque part of the shell, in which 
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