156 A BOOK OF WHALES 



at most. But as to the present species and the 

 remarks appear to fit all the species of Balcenoptera 

 Professor Collett says : "All the whalers are unanimous 

 in opinion that B. borealis (as well as B. musculus and 

 B. sibbaldii) can remain under water for a far greater 

 time than is generally supposed. The duration of 

 this time is estimated to be from eight to twelve 

 hours." This is, if true, a most extraordinary fact. 

 The whales are fished from the shore, and the best 

 period is from the 24th June to the 8th July ; after 

 this they leave the shore on the advent of B. musculus 

 and B. sibbaldii. B. borealis seems to feed entirely 

 on Crustaceans, chiefly the little Copepod Calanus 

 finmarchicus. 



This species may be recognised by its very high 

 dorsal fin. The two sexes show no difference in size. 



The furrows on the throat are about 38-58 in 

 number. The adult female has twenty-six hairs on 

 each side of the lower jaw. In the foetus there are 

 more ; thirty-four were counted on the lower and 

 eleven on the upper jaw. 



The baleen plates are usually black and the bristles 

 white. But there is sometimes a mottlino- or even a 



o ' 



few of the foremost plates may be white. The blow 

 holes lie in two long furrows, between which is a 

 shorter furrow. 



Balcenoptera rostrata, Gray.* Length 25-33 feet. 

 Proportion of height to length as 1:5. Colour greyish 



* Zool. Er. and Terror, 1846, p. 50. For the structure of this species 

 see TURNER, Proc. Roy. Sac., Ed., 1892, p. 36. CARTE and MACALISTER, 

 Phil. Trans., 1868, p. 201 ; J. B. PERRIN, Proc. Zool. Soc., 1870, p. 805. 



