_Rhachianectes_, with but one species, _R. glaucus_,[241] the "Californian Grey Whale," is the last genus of the family Balaenopteridae. This Whale is but imperfectly known anatomically; but quite sufficient has been ascertained to show its great divergence from _Balaenoptera_ or _Megaptera_. The dorsal fin is completely absent, and the throat pleats, so characteristic of the typical Balaenopteridae, are reduced to two. It has, however, the general outline of a Rorqual, with a relatively small head. In osteological characters it tends to unite the two families Balaenopteridae and Balaenidae (if they are really necessary subdivisions). The skull is on the whole Rorqual-like; but its fore-part is narrow as in the Greenland Whale, and the premaxillaries are pinched up in the middle line so as to be visible from the side; this again is a Balaenid character. The cervical vertebrae are free as in Rorquals, and the sternum is quite as in that group. The scapula has more the shape of that of _Balaena_. _Rhachianectes glaucus_ is confined to the Pacific, and has been extensively hunted from the shore. It is not, however, a very valuable Whale, since the baleen is short as in Rorquals, and the {358} beast, moreover, appears to be fierce, a somewhat rare attribute of Whales. It has been spoken of, indeed, as "a cunning, courageous, and vicious" animal. _Rhachianectes_ is essentially a coast Whale, and loves to lie in the surf in quite shallow water waiting for the tide to float it off. This Whale varies much in colour from black to mottled grey and black, and reaches a length of about 40 feet. FAM. 2. BALAENIDAE.--The Right Whales of the genus _Balaena_ are to be distinguished from _Neobalaena_ and from the Rorquals by the following characters:-- The size is large, 50 to 60 feet. There is no dorsal fin. The head is more than or nearly one-fourth of the entire length of the animal. The baleen is very long. The throat is not grooved. The orbital process of the frontal is not wider than the downward process of the maxilla. The cervical vertebrae are all fused. The scapula is rather high. The hind-limb has the rudiment of a tibia. The intestine has no caecum.