Part 49 (1/2)

PHYSETERIDAE--THE CACHELOTS OR SPERM WHALES.

_GENUS EUPHYSETES_.

NO. 270. PHYSETER _or_ EUPHYSETES SIMUS.

_The Snub-nosed Cachelot_.

NATIVE NAME.--_Wonga_, Telugu.

HABITAT.--Bay of Bengal.

DESCRIPTION.--The general form of this animal resembles the porpoise, but the position of the mouth at once distinguishes it. It is small and situated, like that of the shark, considerably under the blunt rostrum, so much so as to lead one to conjecture whether or not it turns on its back in seizing its prey, as do the sharks. The blow hole is crescentic, but eccentrically placed to the left of the middle line of the head, and the horns of the crescent are turned diagonally backwards--that is to say, the lower limb points to the back whilst the upper one touches the middle line and points across; the eye is small; the pectoral fins are triangular, about one foot in length and four and a-half inches broad in the male, and four inches in the female; the dorsal fin is sub-falcate, standing about a foot high, and is nine to ten inches broad at the base, the male being the broader; the colour is a s.h.i.+ning black above, paler and pinkish below.

Dent.i.tion: 1--1/9--9 = 20.

SIZE.--Six to seven feet.

The peculiarity of this cetacean is the preponderance of the cranial over the rostral part, more so, as Professor Owen remarks, than in any other species. The asymmetry of the bones too is remarkable, although this is characteristic of all the catodon whales, especially as regards the bones of the anterior narial pa.s.sages, the left of which is very much larger than the right. This is also the case in the large sperm whale, but in _Euphysetes_ the disproportion is still greater. In a notice on a New Zealand species (_E. Pottsii_), by Dr. Julius Haast, he gives the difference as fifteen times the size of the right aperture; the mouth is also peculiar from its position and small size, being very much overshot by the snout. It may, as Dr. Haast supposes, be a ground feeder, existing on the smaller hydroid zoophytes, otherwise it must, I think, turn on its side in seizing its prey.

MYSTICETE--WHALEBONE OR BALEEN WHALES.

_GENUS BALAENA--THE RIGHT WHALES_.

They are distinguished from the last group by their enormous heads, with more symmetrical skulls, the facial portion of which is greatly in excess of the cranial. The bones of the lower jaw are not united at the symphysis, but are held together by strong fibrous bands; the two rami are very much rounded and arched outwards; there are no teeth.

The maxillary and premaxillary bones are much produced, forming a rostrum tapering, narrow, compressed and much arched in the right whales. From this depends the ma.s.s of whalebone, which grows from a fleshy substance ”similar,” as is aptly described by Dr. Murie, ”to the roots of our finger-nails. It grows continuously from the roots like the latter, and in many respects corresponds, save that the free end is always fringed. Baleen, therefore, though varying from a few inches to a number of feet long, in fact approximates to a series of, so to say, mouth nail-plates, which laminae have a somewhat transverse position to the cavity of the mouth, and thus their inner split edges and lower free ends cause the mouth to appear as a great hairy archway, shallower in front and deeper behind”

(Ca.s.sell's Natural History).

The object of this vast amount of whalebone is to strain from the huge gulps of water the mollusca, &c., on which this animal feeds.

The tongue of these whales is very large, filling up the s.p.a.ce between the lower jaws. The gullet is small in comparison. The nasal aperture differs from the _Denticete_ in being symmetrical, that is, having the double aperture, and in being directed forwards as in most mammals, instead of upwards and backwards as in the dolphins. The whale produces generally one at a birth, which it suckles for some length of time. The mammae are pudendal. The right whales have no fin on the back; those that have form a separate genus, Balaenoptera, i.e. fin-whales.

They are the most valuable of the cetacea, except perhaps the cachelot or sperm whale, as producing the greatest amount of oil and whalebone. Of the various species the most sought after is the Greenland or right whale (_Balaena mysticetus_), which ordinarily attains a length of fifty to sixty feet. An average whale between forty and fifty feet in length will yield from sixty to eighty barrels of oil and a thousand pounds of baleen.

[Ill.u.s.tration: Skull of Baleen Whale. Br, brain cavity; J J*, upper and lower jawbones; the arrows indicate narial pa.s.sages; S, spout-hole; W, whalebone; _t_, tongue in dotted line; _n_, nerve aperture in lower jaw; _bo_, bone sawed through.]

Formerly all whaling vessels were sailers, but now powerful steams.h.i.+ps are used, and the harpoon often gives way to the harpoon gun. A whale, when struck, will sometimes run out a mile of line before it comes up again, which is generally in about half an hour.

The whalers judge as best they can, from the position of the line, in which direction he will rise, and get as near as possible so as to use the lance or drive in another harpoon. When killed, the animal is towed to the vessel and fastened on the port side, belly uppermost, and head towards the stern; it is then stripped of its blubber, the body being canted by tackles till all parts are cleared. The baleen is then cut out, and the carcase abandoned to the sharks, killer whales, and sea birds.

The baleen whales are not found in the intertropical seas. Of the known species there are the Greenland whale (_B. mysticetus_), the Biscay whale (_B. Biscayensis_), the j.a.pan whale (_B. j.a.ponica_), the Cape whale (_B. australis_), and the South Pacific whale (_B.

antipodarum_).

_GENUS BALAENOPTERA--FINBACK WHALES OR RORQUALS_.

Are distinguished by their longer and narrower bodies, smaller heads, being one-fourth instead of one-third the length of the body, smaller mouths, shorter baleen, plaited throats, and smaller flippers; they have a dorsal fin behind the middle of the back, and the root of the tail is compressed laterally. They also present certain osteological differences from the right whales; the latter have the whole of the seven cervical vertebrae anchylosed, that is to say generally, for sometimes the seventh is free. In the finbacks the cervical vertebrae are, as a rule, all distinct and free, although occasionally anchylosis may take place between two or more of them. The sternum of the _Balaena_ consists of a broad, flattened, heart-shaped or oval presternum. ”In the fin whales (_Balaenoptera_) it is transversely oval or trilobate, with a projecting backward xiphoid process”

(_Professor Flower_). The ulna and radius in the rorquals are also comparatively longer than in the baleen whales. In the skull, the supraorbital processes of the frontals are broader in the rorquals than in others, and the olfactory fossa is less elongated.