UNIVALVE MOLLUSKS 111 
Tornatina eximia, Baird, the Excellent Lathe- 
shell, resembles T. culcitella, though it is smaller; 
but it differs in having a more depressed spire, a 
longer and narrower aperture, and a smaller plait 
on the columella. It is found in Puget Sound, and 
also at San Diego. 
Tornatina cerealis, Gld., the Grain Lathe-shell, 
has a minute white shell, less than a quarter of 
an inch in length. It is quite solid, and has a spire 
rounded at the apex. 
Cylichna alba, Brown, the White Cup-shell, is 
another of these small species of shells which re- 
semble little rolls of cloth. This species has a 
white shell, 10mm. long, which is somewhat eylin- 
drical, and tapers towards both ends. It occurs 
in southern California, and also on the Atlantic 
shores. 
Volvula cylindrica, Cpr., the Roll-shell resembles 
the last species, but 1s somewhat flattened in the 
middle, and has an extended umbilical point. 
‘Like a grain of rice, pointed at one end.’’ (Cpr.) 
The fine shell shown in Figure 
97 is named Bulla gouldiana, Pils- 
bry, Gould’s Bubble-shell, (Bulla 
nebulosa). It is thin, polished 
and mottled, resembling a large fi J 
bird’s egg. The spire is depress- [vy 
ed, or more strictly speaking the \ 
body-whorl is elevated above the 
original spire. This species lives 
in the south. I have gathered 
them abundantly at San Pedro, 
