THE BRITISH MAMMALS : THEIR GENERA AND SPECIES. 27 



in the flippers there are four digits, and not five. It spouts higher 

 than any other whale. The body is long and fine in its lines it can 

 travel at twelve knots an hour and the flippers average a seventh 

 of its length over all. There are sixty-five vertebrae and sixteen ribs. 



The Common Rorqual has sixty-three vertebrae and fifteen ribs 

 and has been measured up to seventy feet long. The flippers are 

 an eighth of its length, and, like the tail, are dark above and 



COMMON RORQUAL. 

 (Balanoptera musculns.) 



white below. The throat-folds are more numerous than in any 

 other British species. The body is more slenderly built than that 

 of the blue whale, but the possible speed is not so great. This 

 species is a somewhat frequent visitor to British waters, in chase of 

 the herrings and other fishes on which it feeds. 



The Northern, or Rudolphi's Rorqual, has from fifty-four to 

 fifty-six vertebrae and thirteen ribs, and rarely exceeds fifty feet in 

 length. The flippers are only an eleventh of the body length, and, 

 like the tail, are black, the colour of the body being bluish black 

 above and white below. In contrast to the short flippers the dorsal 

 fin is higher than in the other species, and placed rather more 

 forward. Representatives of this species have appeared and been 

 captured in the Thames and Medway and elsewhere on the east 

 coast during the last thirty years. One over thirty-five feet long 

 was found aground at Tilbury in 1887 with its muzzle nearly level 

 with the river wall, the water in the dock being crowded with sprats, 

 eels, and shrimps, which it seemed to have chased in. 



The Lesser Rorqual does not exceed thirty-three feet in length, 

 It has forty-seven vertebrae and eleven ribs, and its flippers are 

 an eighth of its total length. It is longer in the muzzle than the 

 others, and at once distinguishable from them by the white band on 



