108 LIMN@A. 
27. LIMNAA ADELIN A, Tryon. 
Plate 18, fig. 6. 
Shell thin, semi-transparent, body whorl 
large, wide, convex; spire small, consisting of 
five convex volutions, attenuating rapidly to 
an acute apex, sutures impressed; inner lip 
thin, reflected, but not covering the umbilical 
fissure, which is narrow; columella twisted ; 
color light horn, polished within the aperture, 
outer lip tinged with red within. 
Length 14, diam. 8°5 mill. 
San Francisco, and other localities in Cali- 
fornia. 
This shell is nearly allied to L. catascopium, 
Say, but it may be distinguished by being more 
fragile, more transverse, with a smaller, more 
rapidly attenuating spire, but principally by 
the presence of an umbilical fissure, which in 
catascopium is entirely concealed by the ap- 
pression of the labium. 
(82) 
