12 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [306] 
XXIV, fig. 152.) This species is more at home at the depth of a few 
fathoms, among algze. Another still smaller and lighter colored species, 
which often eceurs abundantly in similar situations, both on alge 
and under stones, is the Rissoa aculeus, (Plate XXIV, fig. 141,) but this 
generally seeks more sheltered situations. All these shells feed upon 
the algw. With them there can usually be found large numbers of sev- 
eral carnivorous species. The most abundant one is a small but pretty 
shell, having a smooth surface and quite variable in color, though usually 
reddish or purplish brown, and irregularly mottled or banded with yel- 
lowish or whitish, the light-colored spots often taking the form of cres- 
cents, and varying much in sizeandnumber. Thisis the Astyris lunata, 
(Plate XXI, fig. 110.) It lives among the alge, and also among 
hydroids, and may be found in almost all kinds of localities, both above 
and below low-water mark. It is usually abundant on the under sides 
of rocks among hydroids, &c., and can nearly always be found in 
the tide-pools. Another allied species of larger size, and much less 
common, the Anachis avara, (Plate X XI, fig. 109,) often occurs with it. 
Clinging to the rocks, or sheltered in the crevices and on their under sur- 
faces, a much larger, dull-white or grayish, roughly-sculptured shell can 
usually be found in abundance. This is the Urosalpinx cinerea, (Plate 
XXI, fig. 116,) which the oystermen call * the drill,” a name very suggest- 
ive of its habits, for it gets its living, like many other similar univalve 
shells, by drilling a round hole, by means of the sharp, flinty teeth that 
cover its tongue, through the shells of oysters and other bivalves and 
then sucking out the contents at its leisure. Itis usually very abun- 
dant on the oyster-beds, and often proves very destructive. Another 
shell of about the same size, somewhat resembling the last, and having 
similar habits, is often found associated with it on the more exposed 
rocky points, as at Nobska Point, the Wepecket Islands, &e. This is, 
however, a very northern and arctic shell, which extends also around 
the northern coasts of Europe, and is called Purpura lapillus, (Plate 
XXI, figs. 118 and 119;) it is here near its southernmost limits, for it 
is not not found in Long Island Sound or farther south; while the former 
is a southern shell, abundant on the whole southern coast as far as the 
Gulf of Mexico, and rare north of Cape Cod, except in a few special 
localities of sheltered and warm waters. The Purpura is seldom found 
living much below low-water mark, and prefers the exposed rocky head- 
lands on the ocean shores, where it flourishes in defiance of the break- 
ers. It lays its eggs in smooth, vase-shaped capsules, attached to the 
sides or under surfaces of stones by a short stalk, and usually arranged 
in groups, (Plate XXI, fig. 120.) The eggs of “the drill” are laid in 
similar places, but the capsules have very short stalks, or are almost 
sessile, and are compressed, with an ovate outline, and angular ridges 
pass down their sides. The “limpet,” another northern and European 
shell, having a low conical form, is occasionally found clinging to the 
rocks at low-water in this region, but is far more common north of 
