126 A BOOK OR WHALES 



acter of importance mentioned in the diagnosis of 

 the genus is the existence of fifteen pairs of ribs, a 

 character which exactly fits in with the assumption 

 that this whale is nothing but a specimen of Balcena 

 austral is. 



Capered, the New Zealand whale, has even less 

 claims if possible to be considered a valid genus. 

 It is practically based upon a slight difference in the 

 form of the tympanic bone. The slight development 

 of the acromion is apparently a question of age and 

 deficient ossification. 



Finally, there is Eubalcena to be considered. The 

 main characters of this are that it has fifteen pairs 

 of ribs, of which the first is not bifid. It seems to 

 be merely a "variation on the theme" of Balccna 

 australis. As to species of this genus Bal&na, there 

 can be no question of the existence of two, the 

 Greenland whale B. mysticetus, and the southern 

 Right whale B. australis. The former is extremely 

 limited in range, being entirely confined to the polar 

 seas ; the latter is world-wide, and probably includes 

 all the whales already spoken of under the various 

 generic names already criticised. 



Baltzna mysticetus. The species may be thus char- 

 acterised : Length, 50-65 rarely 70 feet ; head \ of 

 the length of the body; whalebone, 10-11 rarely 13 

 feet in length ; colour, black, under part of jaw white ; 

 13 pairs of ribs; about 54 vertebrae. This, the 

 Greenland whale, Right whale or whalebone whale, 

 is a purely polar species, never descending as far as 



