It has of late years been ascertained that the Japanese have a very extraordinary opinion of the medical virtues of these tusks. A Dutch merchant, on his return to Europe, happened, among other curiosities, to transmit one of them to a friend in Japan, who by the sale of it became extremely rich. From that time the Dutch wrote, to their correspondents in Europe, for as many as could be sent, and great profit was made of them; and, although by the continued importation, the price has since been considerably diminished, it still continues very high. Narwals are quick, active, and inoffensive animals. They swim with considerable velocity. When harpooned they dive in the same manner as the whale, but not so deep. They generally descend about two hundred fathoms, after which they return to the surface, where they are dispatched, in a few minutes, with a lance. 118. _The GREAT or GREENLAND WHALE_ (Balæna mysticetus, Pl. 1, Fig. 17) _is a marine animal of immense magnitude, measuring from fifty to eighty feet in length, of which the head is nearly one third, and having several horny blades in the upper jaw, and a spiracle or breathing hole on the upper part of the head._ _The bulk of these animals is such that their greatest circumference is nearly equal to their length; and their weight has been known to exceed 400,000 pounds. The mouth is of enormous size, extending as far back as to the eyes; and the tongue is sometimes eighteen or twenty feet in length, and nine or ten in width. Notwithstanding this, the_ gullet, _or passage of the throat, is seldom more than four or five inches across. The eyes are situated a little above the corners of the mouth, and are scarcely larger than those of an ox; and the external opening of the ears, which are merely auditory holes, is likewise very small. There is a large fin on each side of the breast, and the horizontally flattened tail-fin is equal to about one sixth part of the length of the animal. On the back there is neither fin nor protuberance. The skin is very thick and strong, entirely destitute of hair, and always covered with an oily substance which issues through the pores, and which, when exposed to the rays of the sun, makes the surface appear as resplendent as that of polished metal. Whales vary much in colour; some being entirely black, others reddish, or black above and white beneath, and others variously mottled with black or brown and white._ _The great whales are inhabitants of the ocean, and found chiefly in the Greenland and other seas, near the Arctic Pole; they, however, sometimes migrate so far south as to be seen in the neighbourhood of the British shores._