in turn eaten by true carnivora. The water-weeds, both when living and
decaying, are eaten by the entomostraca, the entomostraca are eaten by the
larvae of insects, the perfect insects are eaten by the fish, and the fish
are eaten by men, otters, and birds. Thus we eat the products of the water
plants at four removes in a fish; while we eat that of the grass or
turnips only in a secondary form in beef or mutton.

The water-shrimp is a very common crustacean in the small Thames
tributaries, and valuable as fish food. It has a very rare subterranean
cousin known as the _well shrimp_. A lady in the Isle of Wight, who in a
moment of energy went to the pump to get some water to put flowers in,
actually pumped up one of these subterranean shrimps into a glass bowl.
The well was eighty feet deep. The shrimp was absolutely white, and
probably blind.

Flesh-eating insects are fairly common on land; wasps will actually raid a
butcher's shop, and carry off little red bits of meat, besides killing and
eating flies, spiders, and larvae. Dragon-flies are the hawks of the
insect world, and slay and devour wholesale, when in the air as well as
when they are larvae on the water, though few persons actually witness
their attacks on other creatures, owing to the swiftness of their flight.
Some centipedes will attack other creatures with the ferocity of a
bulldog. An encounter between one of the smaller centipedes and a worm is
like a fight between a ferret and a snake, so frantic is the writhing of
the worm, so determined the hold which the hard and shiny centipede
maintains with its hooked jaws. But the ferocity and destroying appetite
of some of the water creatures would be appalling were it not for their
small size. The desire of killing and devouring appears in the most
unexpected quarters, among creatures which no one would suspect of such
intentions. Of two kinds of water snail found in the Thames, and among the