WHALES AND PORPOISES 45 



of the family. They are ranged transversely across the palate, 



exactly like the furrows in the epithelium.^ In the right whales 



these plates are so long that, however widely the mouth is opened, 



they still close up the intervals between the jaws. 



The right whales open their mouths when they 



find themselves in the middle of shoals of minute 



crustaceans and pteropods," and then close the 



mouth, forcing out the water through the sieve 



of the whalebone. The tiny organisms that are 



prevented from escaping by the fringe of the 



baleen plates then fall on to the broad tongue 



which lies in the great hollow of the under jaw, ciio^ie Umadna. 



d^i • 11 1 1 11 The little Pteropod 



m this manner are swallowed through the moiiusc (bright 



very narrow gullet. In the right whales the p^^'p^^ in colour) 



1 . , 11 1 • 1 1 oil which the 



throat is so narrow at the swallow that it would great whalebone 

 probably allow nothing to pass of larger size than whaies feed (hfe 

 a mouse. When the mouth is shut the long 

 fringes of whalebone fold backwards, the front plates lying below 

 the hinder ones, so that in a sense the long ends of the whalebone 

 are partially contained within the approach to the gullet. When 

 the animal opens its mouth wide the whalebone springs forward 

 till it is perpendicular. 



All the whalebone whales are considered to be characterised 

 by possessing only four true fingers in the flipper, as against the 

 five that are generally found in the toothed whales. There is 

 a seeming exception to this in the right whales, where the hand 

 appears to be five-fingered ; but it is the opinion of Mr. Beddard 

 that the presumed first finger of the right whale is really the 

 prepollex, the additional finger which occasionally appears in 

 mammals before the first or thumb, and which no doubt in this 

 whale has been retained or developed for the support of the 



^ These furrows exist even in the human palate. 



^ The principal source of the right whale's food is a pteropod mollusc 

 about an inch long, named Clione limacina, bright purple when alive. 

 Specimens of this little creature are exhibited in the admirably organised 

 Whale Gallery at the British Museum (Natural History). 



