Section I. MYSTICETE (cf. p. 57).

Mysticete, Gray, Cat. Seals & Whales B. M. pp. 61, 68; Synops. Whales & Dolph. p. 1.

Mystacoceti or Balænoidea, Flower, Trans. Zool. Soc. vi. p. 110.

Head large, depressed. Teeth rudimentary; they never cut the gums. Palate with transverse, fringed, horny plates of baleen. Nostrils separate, longitudinal. Gullet very contracted. Tympanic bones simple, large, cochleate, attached to an expanding periotic bone, which forms part of the skull.

The baleen of the different Whales may be divided by its structure, by its form, and by its colour. The form and structure often go together.

The baleen consists of two parts:—1, the outer layer, called the enamel coat; and, 2, the central fibres, which form the fringe on the inner edge of the blade: both are well seen in cross sections under the microscope. The outer coat or enamel differs in thickness in the different kinds. Thus it is very thick and forms the greater part of the blade in the Greenland Whale; and in different kinds it gradually becomes thinner, until it only forms a thin coat over the central fibres. The central longitudinal fibres differ in thickness and in number. When they are very slender, as in the Greenland Whale, they form only a single layer between the two coats of enamel, and their produced ends make a very fine, long, flaccid fringe to the inner edge of the blade. In other Whales they are very numerous, in many series, and form a considerable part of the thickness of the whalebone, and make a more or less broad and rigid fringe to the blade. In some the fibres are so thick and rigid that they do not droop, but form an erect ragged edge to the short and broad blade, so rigid, indeed, that the fibres of this kind of whalebone are used to make brushes and brooms.

The whalebone varies in form, from being narrow, elongate, many times as long as it is broad at the base, by many gradations, according to the families or genera, until it is not longer than broad. The longest blades have the most enamel and the finest and most flaccid fibres, which, on the other hand, gradually (as it belongs to different genera) become coarser and more rigid as the whalebone diminishes in length compared with its breadth.

The whalebone or baleen offers exceedingly good and permanent characters for the distinction and characters of the species when its structure and form and colour are properly studied. It is stated that sometimes the character of the whalebone is changed by its preparation, as, for example, being soaked in water for some time before it is brought to this country; but the soaking, although it may slightly alter the surface and make the enamel coat rather thinner, does not alter the general form or microscopic structure of the blades.

In my essay on Whales in the ‘Zoology of the Erebus & Terror,’ 1846, I separated the Right Whales, or Balænidæ, into two divisions—the one having very slender, long, polished whalebone with a single series of fringe, and the second with coarser, shorter, and broader whalebone and a thick coarse fringe. The first was afterwards called Balæna, and the second Eubalæna. M. Beneden seems inclined to adopt this division (see ‘Ostéographie,’ Cétacés, p. 144), observing that the former are confined to the Arctic regions and the other to the more temperate zones; but this is not correct, for Balæna marginata, as I stated in my first essay, has the whalebone quite as polished and as fine as that of the Greenland Whale. It lives on the west coast of Australia and New Zealand, in company with the Black Whale of Australia and the Black Whale of New Zealand (both of which, I have no doubt, have short coarse whalebone). The Whale of the most northern parts of the Pacific yields the north-west-coast whalebone, which is of a very coarse character.

The first section of Whales, with long, slender, elastic, polished, finely fringed whalebone, contains two genera, Balæna and Neobalæna.

The Whales of the second section, which have rough, brittle whalebone, with a thick fringe of coarse hairs, includes four genera, viz. Eubalæna, Hunterius, Caperea, and Macleayius.

It is very true that I have only seen the whalebone in one of these genera, Eubalæna, in connexion with the bones of the animal; but as “the South-sea whalers” (that is to say, those who fish in the Southern and Pacific oceans) have only brought various examples of this kind of whalebone from any of their voyages (except a few blades of the whalebone of B. marginata, which they call “sea-tassel”), we may naturally conclude that all the large Right Whales found in those seas have this kind of whalebone.