243 



have the plicated skin of the throat like that of Megaptera, the 

 furrows being more numerous and close set; but the pectoral 

 fin is comparatively 

 small, the dorsal fin 

 distinct and falcate, 

 and the tail very 

 much compressed 

 before it expands 

 into the "flukes." 

 The Rorquals are 

 perhaps the most 

 abundant and widely 

 distributed of all the 

 whales, being found 

 in some of their 

 modifications in all 

 seas, except the ex- 

 treme Arctic, and 

 probably Antarctic 

 regions. Owing to 

 the small quantity 

 and inferior quality 

 of their whalebone, 

 the comparatively 

 limited amount of 

 blubber, and their 

 great activity and 

 the difficulty of cap- 

 turing them by the 

 old methods, these 

 Whales were not 

 until recently an object of pursuit by whale-fishers; but, since the in- 

 troduction of steam- vessels, and especially of explosive harpoons fired 

 from guns in the place of those hurled by the human hand, a regular 

 fishery has been established on the coast of Finmark. There are four 

 distinct species of this genus in British seas. (1) Balcenoptera sib- 

 baldi, the " Blue Whale," the largest of all known animals, attains a 

 length of 80 or even sometimes 85 feet. Its colour is dark bluish 

 gray, with small whitish spots on the breast ; the baleen is black ; 

 the flippers are larger proportionally than in other Rorquals, 

 measuring one-seventh of the total length of the body; and the dorsal 

 fin is small and placed very far back. This Whale has usually 64 

 vertebrse, of which 1 6 bear ribs. Like the others of the genus, this 

 species seems to pass the winter in the open seas, and approaches the 

 coast of Norway at the end of April or beginning of May. At this 

 time its sole food is a small crustacean (Euphausia inermis) which 



FIG. 81. The right tympanic of Balcenoptera musculus from 

 the inner (A) and outer (B) aspects. J natural size. (From the 

 Proc. Zool. Soc.) 



