144 PHYSA. 
21. PHYSA D’ORBIGNYANA, Lea. 
Plate 7, fig. 8. 
Shell broadly oval, obliquely inflated, widely 
striate, semi-transparent, very fragile, dove- 
color; spire rather obtuse; whorls five, the 
last very large; aperture very large, broadly 
elliptical; outer lip regularly expanded, thick- 
ened and pale saffron color under the margin ; 
columella impressed and slightly thickened in 
the middle, and furnished with a fold. 
Length 14, diam. 8 mill. 
Salt Lagoon, near Monterey, California. 
This species is interesting from the fact of 
its inhabiting water which is quite salt. It is 
very near in outline to heterostropha, Say, but 
it is a rather smaller, thinner species, not quite 
so long in proportion, and the longitudinal 
striz distinguish it at once. These striz are 
rather coarse and distant, and the whole sur- 
face of the whorls is covered over with minute 
parallel strie. The aperture is about three- 
fourths the length of the shell. 
(60) 
