I may here be permitted to explain that, in most large fishes, the jaws are completely filled with formidable teeth, as in the shark, for instance. This rapacious monster--which has been aptly termed the tiger of the sea by us, and which the French, in allusion to the deadly character of its habits, have named Requin, or Requiem, the rest or stillness of death--possesses a most marvellous dental apparatus. Its teeth are not, as might be supposed, fixed in sockets, but attached to a cartilaginous membrane. The teeth, in fact, are placed one behind the other in a series of rows; the first of which, composed of triangular cutting teeth, stands erect and ready for use. But as the membrane continues to grow and advance forward, it slowly perishes, and the teeth drop off, their place being taken by the next row which formerly stood second. These, in the course of time, are succeeded by a third series, which are again followed by others. Now, whales possess no such weapons. Their enormous mouths are not filled with 'tusks or grinders, but fitted instead with vast numbers of oblique laminæ of a softer substance, usually denominated whalebone, which is admirably adapted for the crushing and masticating of soft bodies.' To give an idea of the amazing extent of the harvests of 'whale food,' as the Medusæ are termed, that abound in various parts of the ocean, we need only quote the evidence of various navigators on the subject. One (Lieut. Maury), for example, states, that on the coast of Florida he met with a shoal of these animals, that covered the sea for many leagues, through which his vessel, bound for England, was five or six days in passing. The most singular part of the story is that, on his return some sixty days after, he fell in with the same shoal off the Western Islands, and here again he was three or four days in getting clear of them. The Western Islands here mentioned are, it seems, the great resort for whales; and 'at first there is something curious to us in the idea that the Gulf of Mexico is the harvest field, and the Gulf Stream the gleaner which collects the fruitage planted there, and conveys it thousands of miles off to the living whales at sea. But, perhaps, perfectly in unison is it with the kind and providential care of that great, good Being who feeds the young ravens when they cry, and caters for the sparrow.'