52 
629 Amphissa bicolor Dall. 
“Shell small, solid, pale with brownish bands and 6 convex 
whorls; nucleus eroded in the specimens; suture distinct, not 
appressed, whorls full, with 11-13 narrow rounded ribs extending 
nearly from suture to suture; spiral sculpture of numerous flat- 
tened strap-like cinguli separated by subequal channeled shallow 
interspaces; epidermis thin and yellowish; color of shell pale 
straw color with a brownish base and a brown band extending 
from the periphery half-way back to the suture; aperture about 
equal to the spire, the penultimate rib behind it a little swollen; 
pillar slender, polished white with little callus; canal wide, short, 
recurved; outer lip simple, slightly reflected; not lirate inside. 
Longitude of shell, 14; of aperture, 7.7; maximum diameter of 
shell, 8 mm. Habitat: Dredged by the U. S. Fish Commission at 
various places off the coast from Point Sur to San Diego, and in 
the Santa Barbara channel in depths varying from 124 fathoms at 
the south to 298 fathoms at the north, over a sandy or muddy 
bottom. The operculum is brownish and resembles that of A. 
vesicolor Dall. The brown coloration, though generally disposed 
in bands as described, is variable, and occasionally appears in a 
zigzag pattern on the pale ground, or generally suffused over the 
surface, or even maculated, as in Nitidella. The apex when per- 
fect is probably moderately acute, but is more or less eroded on 
all the specimens.’’—Dall, U. S. Nat Mus pr 15:213, t 20, f Ag 
1892. 
630 Amnicola micrococcus Pilsbry. 
Oasis Nye co., Nevada. Death Valley, Inyo co., Cal. 
631 Amntcola protea Gould. 
Melania exigua Conrad. Phila ac pr 7:269 (F 1855) :—‘“Tur- 
reted; volutions 8, disposed to be angulate and somewhat scalari- 
form above; cancellated, longitudinal lines wanting on the lower 
half of the body whorl; columella reflected; aperture elliptical. 
Length, one-fifth of an inch. Colorado desert, California (Or Le 
Conte). The specimens are numerous and of a chalky whiteness, 
showing that they are all dead shells.’’ 
Living: Dos Palmas spring, Colorado desert, near Salton (Or- 
ecutt). Arizona. 
Quaternary: Colorado desert (Orcutt). 
The most numerous of all the fossil shells found on the desert, 
and though one of the smallest species, its numbers are so great 
as to exceed the others in bulk as well. 
632 Amnicola turbiniformis Tryon. 
Snake river, Idaho, to Truckee river, California. 
633 Amphisphyra subquadrdata Carpenter. 
California. 
634 Amphissa undata Carpenter. 
Catalina Island, California. 
635 Amphithalamus lacunatus Carpenter. 
San Pedro and San Diego, Cal. 
636 Anachis coronata Sowerby. 
Cedros Island, Lower California, to Panama. 
637 Anachis subturrita Carpenter. 
San Diego, Cal. 
Synonym of Columbella subturrita. 
