Page:Popular Science Monthly Volume 15.djvu/258

246 of satisfaction, explain their true nature. To use Darwin's simile, such rudiments are like letters in a word which have become obsolete in pronunciation, but which are retained in the spelling, and serve as a clew to the derivation of the word.

In the course of these remarks allusion has been made to more than one species of whale, and it may, therefore, form a study of some interest if we endeavor, shortly, to gain an idea of the general relationship and degrees of affinity of the various members of this curious family-circle. The whale order includes several of the divisions to which the zoölogist applies the name of "families," indicating, by this latter term, a close affinity in form, structure, and habits between the members of each group. First in importance among these families comes that of the whalebone whales (Balænidæ). Here we find family characters in a head disproportionately large when compared with the body as a whole, while the muzzle is sloping, and of rounded conformation. Teeth are absent, as we have seen; whalebone-plates fringe the palate; and the "blowhole" is single, and exists on the top of the head. Such are the family characters in which the Greenland or Right whale and the still larger Rorqual participate along with the "finner" whales and "humpbacked" whales. There is no back fin in the Greenland whale, but the Rorquals and their neighbors possess this appendage. It need hardly be said that, commercially, the former animal is of most importance; while the Rorquals are famed as the largest of the whales. Specimens of the Rorqual have been captured exceeding a hundred feet in length. One specimen, measuring ninety-five feet in length, weighed 245 tons. Next in importance to the Greenland whale and its relatives may be mentioned the family Physeteridæ, of which the sperm whale is the representative form. Here, the head reaches literally enormous proportions, and may make up fully one third of the body. A blunt, square muzzle; a lower jaw armed with teeth; an absence of baleen-plates, and a front blowhole—such are the characters of the sperm whale, which gives sperm-oil to the merchant, and spermaceti and ambergris to the man of drugs. A whole host of "small fry" present themselves as near relations of the whales, in the shape of the dolphins, porpoises, grampus, "bottle-noses," and other animals, including the famous narwhal, or sea-unicorn, possessing the longest tooth in the world in the shape of a spiral ivory pole, of some eight or ten feet in length. Here also the Beluga catodon, or "white whale," finds a zoölogical home, this latter form being the species of which more than one specimen has been recently exhibited in London. The beluga, being a member of the dolphin family, is a "whale" by courtesy only. Like the other members of this group, its blowhole is single and crescentic in shape, and both jaws are well provided with teeth. But the beluga, unlike the dolphins and porpoises, has no back fin, and its muzzle is blunt. This animal, however, is still certainly "very like a whale" in its general