136 PHYBA. 
highly polished; aperture moderate, ear- 
shaped; labrum regularly curved, not thick- 
ened internally; columella much indented at 
its insertion, scarcely folded, narrow, white, 
first vertical, then truncately turning to the 
right towards the base. 
Length 11, diam. 6 mill. 
Sacramento and Marysville, California. 
This shell in appearance is singularly 
graceful and pleasing. Its very smooth, 
shining surface, unmarked by growth-lines, 
and its indented columella, are the most pro- 
minent distinctive characters. 
12. PHYSA NUTTALLII, Lea. 
Plate 7, fig. 2. 
Shell inflated, rather thin, semi-transparent, 
somewhat bright, whitish; spire obtuse, 
short; sutures impressed; whorls four, con- 
vex, the last one large and inflated; aperture 
large, rounded, pale brown within the margin ; 
(52) 
