that is to say, it is long and not very high. The skull is most like that of Balaena, but the process of the frontal arching over the eye is broader relatively than in Balaena, and thus approaches Balaenoptera. Nothing is known of the viscera of this Whale. The whalebone is white, and the animal was first described by Dr. Gray from pieces of "bone." It is not always that so fortunate a diagnosis of specific or generic difference has been made from a structure which apparently offers so little aid for discrimination.
There is but a single species of the genus which is named Neobalaena marginata.[[235]]
Sub-Order 2. ODONTOCETI.
The Odontoceti have teeth but no whalebone; the blow-hole is single; the skull is not symmetrical; some of the ribs are two-headed.
Fam. 1. Physeteridae.—This family of the Odontocetes may be thus defined:—All or most of the cervical vertebrae are fused together. The costal cartilages are not ossified. In the skull the pterygoids are thick and meet in the middle line; the symphysis of the mandible is long. Teeth, more or fewer, are found in both jaws, but those of the mandible are alone functional (? exc. Kogia). The pectoral limb is smallish. The throat is grooved by two or four furrows.
This family of Whales is again susceptible of division into the two sub-families—Physeterinae or Sperm Whales and the Ziphiinae or Beaked Whales. Professor P. J. van Beneden was strongly against any subdivision of what is here regarded as a perfectly natural family, embracing the Physeters and the Beaked Whales. There are, however, some reasons for the subdivision. The Ziphiinae have a reduced series of teeth, never exceeding two on each mandible, which contrasts with the fully-toothed mandibles of both Physeter and Kogia. The stomach of the Ziphioids is extraordinarily complicated even for a Cetacean. The small head of the latter group, which recalls in a curious way that of Mosasauroid reptiles and some Dinosaurs, is in contrast to the
enormous head of the Cachalot and the very fairly-developed skull of the "Pygmy Sperm Whale." Both, however, furnish spermaceti, and in various osteological details come near together. On the whole we incline towards separating the Cachalots from the Ziphioids, and shall therefore commence with the former as being in some respects the more primitive members of the family Physeteridae.
Sub-Fam. 1. Physeterinae.—This sub-family may be thus defined:—Teeth in lower jaw numerous. No distinct lachrymal bone. Stomach with only four compartments (? as to Kogia).
Of this sub-family the best-known genus is Physeter, including the Sperm Whale or Cachalot. Of other reputed species we shall speak later. The genus is characterised in the first place by its large size—as much as 82 feet of length have been assigned to Physeter macrocephalus; but Sir William Flower thought that 55 or possibly 60 feet might be a better approximation to the greatest length of the Cachalot. The head is enormous, a third of the length of the body, and terminates in a massive and bluntish snout. This is, however, not so abruptly truncated as is often represented in figures. According to Messrs. Pouchet and Chaves,[[236]] it slopes forward two metres beyond the end of the lower jaw; the mouth is thus ventral and almost shark-like in position, as is the case also with the Pygmy Sperm Whale, to be considered later. In connexion with this peculiar position of the mouth, it has been asserted—Mr. F. T. Bullen figures it[[237]]—that the Sperm Whale turns over upon its back to bite. The blow-hole is single, and shaped like the sound-hole of a violin; it lies upon one side, and is not median in position. The throat is grooved as in the Ziphioids by two grooves. The dorsal fin is represented by a whole series of lowish humps, decreasing in elevation from before backwards. The pectoral fins are not large relatively speaking. The great square head is not occupied entirely by the skull; the cavity lying above, which is of course traversed by the tube ending in the blow-hole, is filled with the spermaceti, which is fluid fat during the life of the animal. Spermaceti also occurs in other Whales; and that of Hyperoodon, whence it has been extracted for commercial purposes, is said to offer no differences of importance from the spermaceti of the
Sperm Whale. Spermaceti as a drug appears to have been first mentioned in the pharmacopoeias of the famous medical school of Salerno towards the year 1100. But it was confounded with a totally distinct substance, viz. ambergris. The confusion was also made by the famous alchemist Albertus Magnus, and by the observant Archbishop of Upsala, Olaus Magnus, in his work De gentibus septentrionalibus. It was supposed in fact by these writers to be the liberated sperm of the Whale, hence obviously the name. Later on, the substance in question was regarded as the brain of the Cachalot, in fact as late as the middle of the eighteenth century. It was Hunter and Camper who really discovered the true nature of the substance, oil of course, in the cavities of the skull.[[238]] The huge skull of Physeter "is perhaps the most modified from the ordinary type" of skull in the whole mammalian class.