Among them, the Great Blue Shark, from fifteen to twenty-five feet long, and the awful White Shark, known sometimes to reach a length of thirty-seven feet, have an undesirable pre-eminence. These monsters are furnished with teeth, the reverse of “unimportant.” In shape they are generally triangular, serrated, and sharply pointed. In arrangement they occupy rows, the foremost only of which is in actual use. Other rows are folded back and kept in reserve, to be brought forward when required. Thus a shark is never without a ready supply of his formidable weapons. White sharks are much given to keeping in the wake of ocean-ships, on the look-out for scraps thrown overboard. One such persistent follower having been killed, an inventory was made of the contents of its stomach, as follows--“A tin can, a number of mutton bones, the hinder quarters of a pig, the head and forequarters of a bull-dog, and other and smaller things, as the auction-bill says, too numerous to mention.”[11] [11] _Standard Natural History_, ii. p. 83. Closely related to the Sharks are those savage creatures known as Rays or Skates. The larger number of them live usually at the bottom of the sea, in somewhat shallow waters, lying on the ocean-floor, or swimming about just above it. Thus they do not so often come into contact with man as do sharks. But it is want of opportunity, not want of will, which keeps them from doing harm. When they have a chance they seldom fail to use it. Among different branches of the “Ray” division is found the tropical Saw-fish, with its long sharp teeth-laden snout, ever ready to fight the whale. In youth the saw-fish has a strong resemblance to a shark. Then there are the Sting-rays, with barbed spines, a mere touch from which causes a man terrible suffering, as if from poison; while a severe sting may end in death. These are found in South America. There is also the family of Torpedo Rays, quite distinct from the better-known South American Electric Eel, but able to administer electric shocks strong enough to render a man for the time helpless. They are found in many waters--large creatures, rounded in shape, smooth-bodied, thick, with longish tails. Worst of all are the huge ungainly Eagle-Rays and Sea-devils, with their powerful grinding teeth. These grow to an enormous size; and the larger ones are quite capable of upsetting a big boat. Nor would they hesitate so to do, if attacked. One such creature was said to be fifteen feet in breadth, with a tail several feet long; another to have been twenty feet in length; another to have been three or four feet in thickness; another to have weighed well over twelve hundred pounds; another to have needed fourteen oxen to drag its dead body. They sometimes share with Cuttlefish the distinction of being called “Devil-fishes.” These monstrosities are found off Barbadoes, off Jamaica, and in the tropical waters of the Atlantic and Pacific.