300 ZOOLOGY. 



whales,) and the balsense, (whalebone whales balaenae and 

 rorqual,) or whales properly so called, belong to this group. 



The whales are enormous cetaceans, whose head forms 

 about a third of the length of the whole body. In the mouth 

 there are no teeth, but numerous plates of whalebone depend 

 at the sides from the mucous surface of the upper jaw. They 



Fig. 276. Head and Tail of Balaenoptera rostrata.* 



are so arranged as to form towards the mouth a sieve, 

 calculated to retain very small animals, on which indeed 

 these huge cetaceans live. The volume of water they take into 

 the mouth is expelled through the nostrils ; hence the name 

 of blowers and blow-holes given to their anterior or superior 

 nostril s.f Contrary to what might be imagined, these enor- 



Fig. 2774 



* Sketches made by Mr. E. Forbes, who at that time acted as my. 

 assistant. 



t It has been shown by Scoresby, myself, Beale, and a number of other 

 observers, that the pretended jet d'eau is merely the vapour from its lungs. 



t Head of the Eorqual of Fabricius; a whalebone whale. Drawn by 

 Edward Forbes. 



