GASTEROPODS 389 
on a white background, or of white splotches on a brownish back- 
dd. (Plate LXXIV.) 
(Anachis) avara, and the variety C. similis. These rather 
_or shells, about one half to three fifths of an inch long, occur from 
@, -ida northward to Cape Cod. The upper whorls are smooth, the 
‘dw er ones are undulated with vertical costs (ten to thirteen), and the 
body-whorlis encircled below the middle by a series of revolving, closely 
set grooves. The aperture is typical of the genus, though less strongly 
marked by internal callosity on the outer lip and with less prominent 
teeth than in C. mercatoria. The greater development of the revolving 
grooves, which spread over the entire surface of the body-whorl and 
cross the coste, producing a granulated surface, constitutes the variety 
C. similis. The color is brownish, with white reticulations. This species 
is to be found in considerable abundance in sandy mud and among 
stones and alge about low-water mark. At New Bedford and Martha’s 
Vineyard, and on Cape Cod, it may always be taken. It is also common 
at Norfolk and along the Virginia and Georgia coasts. 
C. (Astyris) lunata. One of the characteristic eastern-codst shells, 
which, like the last species, ranges from Cape Ann in Massachusetts to 
the West Indies. It occurs about low-tide mark and just below, upon 
stones and alge, or crawling about on a soft bottom. On account of its 
generic features, combined with the peculiar coloration, the species can- 
not be mistaken. The latter is a ground of reddish-brown or fawn, with 
encircling rows of large white or yellowish spots. The whorls are quite 
smooth. Length not over one fifth of an inch. 
The collector soon learns to recognize the variable forms of these 
northern-range columbellas. They are not a difficult group, for once 
their generic position is established by the characters of the aperture 
(which are constant) the species can readily be determined, notwith- 
standing their tendencies to vary from the type. Californian waters also 
have several columbellas. The conchologists of the west coast have 
preferred to apply to their shells, and indeed to employ in general use, 
a large number of subgeneric names in place of the ordinarily accepted 
generic ones. The result of this is to confuse at first the student of 
conchology, who, though fairly familiar with the molluscan genera, finds 
himself perplexed when he confronts a list of west-coast.shells. Thus 
the two common Californian columbellas are ‘‘ Amphissa” corrugata and 
“ Astyris” gausapata, these two species belonging to different subgenera 
of the genus Columbella. 
C. corrugata. This shell finds its metropolis in Puget Sound, but 
oceurs also along the Californian shore. The aperture is wider than is 
usual in this genus. The surface is deeply wrinkled by longitudinal 
cost and is encircled by revolving grooves. Length one half of an 
inch; color red, or orange to light brown. It is found in shallow pro- 
tected waters. (Plate LXXIV.) 
C. gausapata. This species lives in great numbers about the roots 
of eel-grass. It is very small and smooth, with a rather high spire. The 
color of the spire is deep brown ; the body-whorl is lighter in color. Oc- 
casionally the body-whorl is obtusely carinated just below the suture. 
This little shell is very common upon many beaches after heavy winds, 
but it should, be sought for at very low tides and gathered alive. (Plate 
LXXIV.) 
