222 A BOOK OF WHALES, 



maxillary crests (Fig. 29) are paralleled in Pkyseter, 

 where, however, owing to their relative thinness, 

 they bound, instead of diminishing through blocking 

 up, the cavity for the spermaceti. In the vertebral 

 column too is a striking point of likeness. The 

 first six ribs, as in the Ziphioids, are two-headed, 

 the capitular and tubercular attachments being in 

 two successive vertebrae. The seventh rib, how- 

 ever, is exactly like the tenth rib of the Cachalot. It 

 is attached to two processes of the seventh dorsal 

 vertebra, which nearly join each other before they 

 receive the rib. Pkysetcr, therefore, in this particular, 

 is more like Hypcroodon than it is to its nearest ally 

 Kogia ; and both genera retain a trace of the arrange- 

 ment characteristic of Inia. 



This genus comprises apparently but two species : 

 one, with many aliases (e.g., H. butzkoff, H, borealis], 

 is the northern H. rostratum ; the other, which seems 

 to be perfectly distinct, though only known from a 

 single water and pebble-worn skull, comes from 

 Australian seas, and was described by Sir W. Flower 

 as H. plamfrons. Thus, like so many other genera 

 of Cetaceans, Hyperoodon is of very wide range.* 



Dr. Gray's species, " latifrons" made the type of 

 a separate genus Lagenocetus, was undoubtedly based 

 upon an old example of Hyperoodon rostratum. It 

 has been shown that the "forehead" increases in 

 squareness with the age of the animal, as the accom- 



* The name Hyperoodon was given to this whale (by Lacepede) on 

 account of the numerous rough papillae upon the palate, which were 

 erroneously regarded as teeth. 



