158 A BOOK OF WHALES 



as to length as i : 6f . Colour grey- slate above, 

 white below. Dorsal fin low with straight margins ; 

 placed slightly in front of last fourth of body. Vent 

 corresponding in position with its anterior margin. 

 Pectoral fin \ of total length of body. Plates of 

 baleen dark bluish black, also bristles. Number of 

 plates up to 370. Length 950 mm. 



This is perhaps, speaking from stranded examples, 

 the commonest species of Rorqual. " Specimens are 

 stranded," remarks Mr. Lydekker, "on the British 

 coasts, more especially those of the southern parts 

 of England, almost every year, generally after stormy 

 weather and very frequently during the winter." Dr. 

 Murie, who described many points in the structure 

 of a sixty-foot long individual which was killed at 

 Gravesend in 1859, describes the number of throat 

 plaits as "somewhere about one hundred." In this 

 individual the dorsal fin measured only 15 inches in 

 height. 



A curious asymmetry in the coloration of this species 

 has been noted by more than one observer " a sort 

 of pleuronectism," van Beneden terms it. The body 

 is sometimes paler upon one side than upon the other ; 

 apparently there is no constancy as to which side is 

 the paler or the darker. This Balcsnoptera devours 

 fish, and as many as 800 individuals of Osmerus 

 arcticiis have been found in the stomach of a whale. 

 It is chiefly herrings that it pursues on the coasts 

 of Norway and Great Britain. 



The four species just characterised are the only 



