RORQUALS OR FIN WHALES 210, 



Whale or Sibbald's Rorqual ; the Firmer Whale, Razorback 

 or Common Rorqual ; the Sei Whale or Rudolphi's Rorqual ; 

 and the Lesser Rorqual or Little Piked Whale. A fifth species, 

 closely allied to the Sei Whale, Bryde's Whale, should perhaps 

 be added to the list. Quite a number of other Rorquals have 

 been recognized at one time or another, some on the slenderest 

 of evidence. A single bone, a difference of locality, a difference 

 in colour due to the presence of a film of microscopic unicellular 

 plants, called diatoms, on the skin, have all been made sufficient 

 reason for the creation of separate species, but with the 

 exception of Bryde's Whale, restricted to the South African 

 coast, all the species of the group are world-wide in their range. 

 It is fairly safe to say that there is no specific difference 

 between the Blue Whale found in the North Atlantic and that 

 frequenting the African coast or the seas surrounding the 

 Antarctic, and the same applies to the other members of the 

 group. 



Genus Balcenoptera. 



THE BLUE WHALE OR SIBBALD'S RORQUAL 



(Balcenoptera musculus). Plate VI A. 



The Blue Whale is the largest of all living animals, although 

 in its natural element it does not give one the impression of 

 ungainly bulk or superfluous size. It is only when it is dead 

 and hauled on to dry land that any proper conception of its 

 immensity can be obtained. The general proportions of this 

 species and, indeed, of all the Rorquals are much finer than 

 those of the Right Whales. The girth is much smaller com- 

 pared with tne total length, and the whole outward appear- 

 ance of the animal suggests a greater capacity for speed of 

 swimming. The head is less than a quarter of the total 

 body-length, and while still of considerable magnitude, its 

 bulk is a much lesser proportion of the whole body than it is 

 in the Right Whales. The foremost part of the head is not 

 narrowed and arched, but forms a more or less flattened beak- 

 like extension of the skull with nearly parallel sides to within 

 a short distance of the tip, where the lateral margins bend 

 round to meet each other. When the mouth is closed this 

 rostrum or beak fits in between +he two lower jaws ; the great 



