44 
ANIMAL LIFE ON THE 
carnivorous, they also feed upon decaying vegetables if 
required; and in proof of this, I may mention that for six 
months I had a purple lip, the species from which the 
famous mollusc dye was extracted, with nothing to live 
upon that I could trace but vegetable matter, and when, 
at the end of that period, liberated from the tank and 
placed once more on its native beach, it seemed as healthy 
and active as ever. 
There are no grave-diggers in the sea — then what be- 
comes of all the carcases of the animals, great and sriiall, 
that die ? To rid the ocean of the putrefaction of death, 
and keep its waters sweet, and guard against overproduc- 
tion, has not been neglected by the Creator in his infinite 
wisdom, and in both these departments this family in its 
various branches performs an active part. But our speci- 
men has now reached the^ clump of mussels, and is 
settling down upon the broad side of one of them. For 
a full quarter of an hour we watch the creatures, but both 
animals remain as motionless as the stones. Stooping 
down, we see the whelk is still holding on with a firm or 
vacuum grasp of the foot; but plucking him up, which re- 
quires some little force, we find that he has already drilled 
through the stone-protected covering of his victim, and 
feasted upon the savoury flesh within. Taking up the 
mussel, and holding it between us and the sun, the beautiful 
ultramarine colour of the shell fills the eye, streaming 
through the sucked-out cavity within. The spot selected 
for attack is invariably near the middle of the shell, an 
instinctive reason no doubt in the animal to guard against 
the seizure or injury of its wimble should the valves of his 
victim happen to open and close; likewise as the spot 
within that contains the most easily extracted food. 
In his attacks on the common black whelk he never 
