Most of the whalebone which we use is obtained from the bowhead, or Greenland whale, which is found in the northern seas. This animal is from forty to sixty feet long when fully grown, and the baleen plates are often ten or even twelve feet in length, while there are nearly four hundred of them on each side of the upper jaw. In a large whale these plates weigh more than a ton, and are worth at least $15,000. Then from 130 to 150 barrels of oil will be obtained from its blubber; so that a big Greenland whale is a very valuable animal. But whales of this size are now very rarely met with, and there seems to be some danger that before many years have passed away these giant creatures will be almost extinct. RORQUALS The rorquals are sometimes known as fin-whales, or finbacks, because they have an upright fin on the hinder part of the back. They are not so valuable as the Greenland whale, because their baleen is of inferior quality, and is very much shorter, while their blubber does not yield nearly so much oil, and they can swim with such speed that they are very much harder to catch. The common rorqual grows to a length of about sixty or sixty-five feet, and is found throughout all the northern seas, and occasionally even in the Mediterranean. It is a solitary animal as a rule, but schools of from ten to fifteen individuals are sometimes met with, and may be seen leaping into the air, and rolling and tumbling about in the water, as though they were having a game of play together. The rorqual feeds partly upon the small creatures which it captures by means of its whalebone strainer, and partly upon fishes. How vast its appetite is you can judge from the fact that as many as six hundred large codfish have been found in the stomach of one of these animals, together with a number of pilchards. Sometimes a rorqual will come quite near the coast, and remain in a fishing-ground for weeks together, and as it swallows several boatloads of fish every day, it is scarcely necessary to say that the fishermen are not at all pleased to see it. There is another kind of whale, called the lesser rorqual, which only grows to the length of about twenty-five or thirty feet. It is common off the shores of Norway, and commoner still in North American waters, where it is known as the sharp-nosed finner. It is a very playful animal, and is said sometimes to gambol round and round a ship for miles, now and then diving underneath it on one side and coming up on the other. [Illustration: TYPES OF BEARS. 1. Polar or Ice Bear. 2. American Black Bear. 3. Brown Bear: Grizzly Bear. 4. A Marine Bear (California Seals).] THE DOLPHIN FAMILY Next we come to the dolphin family, which includes the narwhal, the grampuses, and the porpoises, as well as the true dolphins. THE NARWHAL