GASTEROPODS 389 



lines on a white background, or of white splotches on a brownish back- 

 ground. (Plate LXXIV.) 



C. (Anachis) avara, and the variety C. similis. These rather 

 slender shells, about one half to three fifths of an inch long, occur from 

 Florida northward to Cape Cod. The upper whorls are smooth, the 

 lower ones are undulated with vertical costae (ten to thirteen), and the 

 body- whorl is 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 costse, 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 algae 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. (Astyi-is) lunata. One of the characteristic eastern-coast 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 algae, 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" corrugate and 

 " Astyris" gausapata, these two species belonging to different subgenera 

 of the genus Colunibella. 



C. corrugata. This shell finds its metropolis in Puget Sound, but 

 occurs also along the Californian shore. The aperture is wider than is 

 usual in this genus. The surface is deeply wrinkled by longitudinal 

 costae 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.) 



