THE MANTLE-COVERED ANIMALS. 119 
and other soft animals, yet their chief food is shell- 
fish, and they have to reach them through their 
closed houses. The hungry whelk therefore has to 
bore a hole through a solid shell before he can take 
his meal, and for this he is provided with a boring 
instrument such as any engineer might envy. His 
snout, which can be stretched out like the trunk of 
an elephant, contains a toothed rasp like the peri- 
winkle's but much more formidable ; and this rasp is 
moved up and down by powerful muscles so as to 
act like a fine saw drilling a neat round hole even in 
the hardest shell, through which he can suck out the 
soft body it contains. It is curious that he does not 
always know when he will find food within, for he 
will sometimes drill a hole not only in an empty 
shell, but even in a shell-like stone. 
While the periwinkle and his relations then are 
grazing on the seaweed, the whelks and cowries, 
and their tribe, are finding means to attack the 
oysters and cockles, limpets and periwinkles, and so 
to establish a successful hunting-ground where there 
would be no room for more vegetable-feeders ; and 
you can scarcely pick up a handful of shells without 
finding some pierced with the holes made by these 
marauders. They people the shores of the ocean all 
over the world, some carrying their eggs till they are 
hatched, some glueing them down in safe nooks, others, 
such as the whelk, laying them in a bunch of horny 
bags (E, Fig. 45), in each of which the young whelk 
may be seen moving, if you can pick them up fresh 
from the sea. And when the little ones are born, 
they are able to swim about, as the young oyster 
was, and while myriads are borne away on the sea 
