So sharp are its triangular teeth, arranged like those of the shark, that neither twine, copper, nor steel can withstand them. At the sight of any red substance, blood especially, they swim forward to the attack; and as they usually move in swarms, it is extremely dangerous for man or beast to enter the water with even a scratch upon their bodies. Horses wounded by the spur are particularly exposed to their attacks when fording a stream; and so rapid is the work of destruction, that unless immediate assistance is rendered, the fish soon penetrate the abdomen of the animal and destroy it: hence the name given to them by the Spaniards means "tripe-eater." When a net is drawn on shore, numbers of these little pests are seen jumping in the crowd, their jaws wide open, tearing whatever comes in their way, and especially the meshes of the nets, which they soon render useless. Some tribes of natives place their dead in the water, when these creatures speedily eat the flesh off the bones, which are then preserved in baskets. Even human beings, when bathing, or fording rivers, are attacked by these terrible little cannibals;--for cannibals they are, as, whenever any of their own race are killed, they instantly attack and devour them. There are other species of this fish,--among them the black caribe of the Orinoco. There is also a small species--a harmless, pretty little fish, of a bright green colour on the back, and a white belly streaked with pink. The teeth are used by the Macoushi Indians for sharpening the points of their poisoned arrows. This they do by drawing them rapidly between two of the teeth, in the way that knives are sharpened by two circular steel files, now in common use. ADAPTATION OF ANIMALS TO THEIR DESTINED MODE OF EXISTENCE.