CETACEA. 



547 



these external apertures or nostrils are known as the " blow- 

 holes" or "spiracles." The act known to the whalers as 

 " blowing " consists in the expulsion from the blow-holes of a 

 jet of what is apparently water, or at any rate looks like it. ■ The 

 act is performed by the whale upon rising to the surface, and 

 it is usually by this that the whereabouts of the animal is dis- 

 covered. The old view as to what takes place in the act of 

 blowing is, that the- whale is really occupied in getting rid of 

 the surplus water which it has taken in at the mouth and 

 strained through the baleen-plates. The modern and doubt- 

 less correct view, however, is, that the water which has been 

 strained through the baleen really makes its escape at the side 



F.g. 212. — Diagram of the Baleen-plates of a Whale, a a Section of the palatal sur- 

 face of the upper jaw, showmg the strong median ridge or .keel ; b b Baleen-plates, 

 sunk at their bases in the palate ; yy Fibrous margin of B^een-plates. 



of the mouth, and does not enter the pharynx to be expelled 

 through the nose. Upon this view the apparent column of 

 water emitted from the blow-holes in the act of blowing con- 

 sists really of the expired air from the lungs, the contained 

 watery vapour of which is suddenly condensed on its entrance 

 into the cold atmosphere. With the expired air there may be 

 such water as may have gained access to the nose through the 

 blow-hole, for the expulsion of which proper provision exists 



