126 A BOOK OF WHALES 



Both Rhachianectes and Neobalana to some extent 

 interfere with the naturalness of the families Balsenidae 

 and Balsenopteridae ; and so does that less-known 

 genus Agaphehts (if really distinct) with which Cope 

 at first united Rhachianectes. Rhachianectes has the 

 general outline of a Rorqual ; but there is no dorsal 

 fin, and the throat plaits of Baltznoptera are reduced 

 to two. The baleen, however, is short as in the 

 Rorquals. The skeletal characters are also to some 

 extent intermediate. The cervical vertebrae are free, 

 as in Rorquals ; the sternum is as in that group ; and 

 so on the whole is the form of the skull. But when 

 the skull is seen from the side, the pre-maxillaries are 

 as obvious as in the Greenland whale, and the fore 

 part of the skull is narrow as in that cetacean. The 

 scapula, moreover, is not so elongated as in the 

 Rorquals, but has more the shape of that in the 

 genus Balcena. 



Neobal&na is placed by Gray among the Balsenidae ; 

 but it has several Balaenopteroid characters. It is, 

 however, a true Balana in the length of the baleen 

 and in the consequent arching of the skull. 



But the frontal bones, or rather the processes of 

 those bones, which cover over the orbit are broad, 

 as in Balcenoptera, and not so narrow as in the Right 

 whales. The skull, as a whole, is not so dispro- 

 portionate to the body as in the genus Bal&na ; it 

 is more like a Rorqual in this particular. Finally, 

 the scapula is Rorqual-like in its antero-posterior 

 elongation ; it is not nearly so high as in the Right 

 whale. On the other hand, the sternum marks the 

 affinities of Neobaldena with Balesna. 



