380 THE SHELL-FISH OF THE COAST. 
mon species of the Southern shore, wentletrap 
(Scalaria, Pl. 1, Figs. 12, 13), and purple (Purpura 
lapillus, P|. 1, Figs. 9,10). By pressing on the oper- 
culum of the last-named a fluid is released of a dull 
crimson color, much resembling some of the purples 
of antiquity; indeed, it was from one of the species 
of this genus that the ancients obtained some of 
their more highly prized dyes. The purple is a 
rough customer among the oyster- and muscle-beds, 
where its depredations extend as well to the dead 
as to the live animal. It is not, however, satisfied 
with these delicacies alone, but will also venture on 
limpets, barnacles, dead fish, ete. If by habit a 
pirate, the purple in turn suffers from the piracy of 
other animals, and largely so from the seemingly 
harmless hermit-crabs. These have on more than 
one occasion been observed to sally forth under 
protection of their borrowed castles, and clean out, 
so to say, the purple, dragging their unfortunate 
victim from the shell. In one such encounter, as 
narrated by Mr. Crowther, of Whitby, England, 
the attacking party were shielded by the shells of 
four distinct species of snails—a dog-whelk, peri- 
winkle, troque, and purple. 
Partaking largely of the habits of the purple is 
the ‘ drill’ (Urosalpinx cinerea, Pl. 1, Fig. 8), a name 
suggestive of the methods employed by this animal 
to obtain its food. Like the last-named, it is a great 
destroyer of the oyster. 
Our description of this section of the shore-fauna 
would not be complete without a special reference 
to the sandal or slipper-limpet (Crepidula) and the 
