Before we look at some of these fierce creatures, whom everyone dislikes, we will say a word for them. Nature meant them to be _scavengers_, to clean up the sea. And this they do. Dead and decaying flesh is a danger, and the Shark, ever hungry, clears it away quickly. Now and again fishermen bring a big Shark to port, and hang him in the market--not for sale, but as a "show." The Blue Shark is the one most often displayed like this. See how his mouth is set, well under the head, as in all Sharks; and notice the shape of the body. It tells of speed and strength in the water; its pointed, tapering form reminds one of the racing yacht. [Illustration: THE WHITE RAY] What is this fierce fellow doing so near our coast? He is often found off Cornwall--too often, thinks the fisherman. This Shark comes to seek the same prey as the fisherman--the shoals of Mackerel and Pilchard (a cousin of the Herring). Where the shoals go, the Blue Shark follows. The silly Mackerel, all crowded together, have no chance to escape their awful foe. They are nearly as helpless as a flock of sheep with a tiger in their midst. [Illustration: THE ELECTRIC RAY] If the Shark comes across a mass of Mackerel or Pilchards in a net, he looks on them as a fine feast. Dashing at them, he tears the net to pieces, swallowing lumps of netting with great mouthfuls of fish. Small wonder the fisherman detests this savage visitor which causes him such serious loss of time and money. He naturally looks on Sharks as useless "vermin," to be destroyed whenever possible. [Illustration: _Photo: A. F. Dauncey_. DOG-FISH EGG CASE] The Fox Shark, or Thresher, is another fierce visitor to these shores. This savage hunter comes after the Herrings, Pilchards and Sprats. It is said to hunt these useful little fish in a strange way. As you know, they travel in shoals. The Thresher swims rapidly round and round them. Nearer and nearer it comes to the unlucky little fish, and they crowd together, huddling up in a helpless mass. The Thresher adds to their panic by _threshing_ the water with its terrible tail. And then, as you can well imagine, it dashes at them and devours an enormous meal. Half the length of the Thresher is tail. Not long ago there was landed at one of our fishing ports a Thresher Shark of half a ton, its tail being over ten feet in length. Even the great Whale has reason to fear the fierce lashings of that long, whip-like weapon! Our commonest Sharks are those small ones known as Dog-fish, which you can often see at any fish market. They are good to eat, though not used much as food. Though small in size, they are large in appetite and fierce in nature. Like savage dogs, they hunt in packs, waging war against the Whiting, Herring and other fish. [Illustration: THE SHARK]