508 MANUAL OF ZOOLOGY. 



baleen really makes its escape at the side of the mouth, and 

 does not enter the pharynx to be expelled through the nose. 

 Upon this view the apparent column of water emitted from the 

 blow-holes in the act of blowing consists really of the expired 

 air from the lungs, the contained watery vapour of which is 

 suddenly condensed on its entrance into the cold atmosphere. 

 With the expired air there may be such water as may have 

 gained access to the nose through the blow-hole, for the expul- 

 sion of which proper provision exists in the form of muscular 

 diverti cula of the nasal cavity. It is also possible that the 

 column of air in being forcibly expelled from the blow-hole 

 may take up with it some of the superincumbent water. 



The skin in the Right Whale is perfectly smooth and 

 naked, but it is underlaid by a thick layer of subcutaneous fat, 

 which varies from eight to fifteen inches in thickness, and is 

 known as the " blubber." The blubber serves partly to give 

 buoyancy to the body, but more especially to protect the ani- 

 mal against the extreme cold of the medium in which it lives. 

 It is the blubber which is chiefly the object of the whale-fishery, 

 as it yields the whale-oil of commerce. 



The whale which is captured in the Antarctic regions is not 

 the same species as the Greenland Whale, and is termed the 

 Balana australis. It is much about the size of the Right 

 Whale, averaging about fifty feet, but the head is proportion- 

 ately smaller. This whale is an inhabitant of the greater part 

 of the Pacific out of the regions of the tropics; but it is chiefly 

 captured when approaching land, which the females do for the 

 purpose of bringing forth their young. 



The only remaining members of the Bal&nidce, which require 

 notice are the Rorquals and Hump - backed Whales, consti- 

 tuting the group of the " Furrowed " Whales. These are col- 

 lectively distinguished by having the skin furrowed or plaited 

 to a greater or less extent, whilst the baleen-plates are short, 

 and there is a dorsal fin. The specific determination of these 

 animals is a matter of great difficulty, but there would appear 

 to be two very well marked genera: i. The genus Megap- 

 tera, including the so-called Hump-backed Whales, in which the 

 flippers are of great length, from one-third to one-fifth of the 

 entire length of the body. 2. The genus Baltznoptera, compris- 

 ing the so-called Rorquals or Piked Whales, in which the flip- 

 pers are of moderate size. 



In both genera there is a dorsal adipose fin, so that they are 

 both " Finner " Whales. The Baltznoptercz reach a gigantic 

 size, being sometimes as much as eighty or one hundred feet 

 in length. They are very active animals, however, and their 



