234 GUNDLACHIA. 



shining and j)ui"plish, 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, Stlmpson. 

 Plate 2, figs. 22—24. 



Full grown shell in general form ovate, 

 aperture less ovate than in G. Galifornica' 

 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 pommences its life as an Ancylus, 

 the dorsal opaque part of the shell, in which 

 (28) 



