The Cctacea, or Whales. 1 1 1 



similar circumstances. The mode of life of the 

 whales, however, differs completely from that of other 

 mammalia, the breathing apparatus being modified in 

 such a manner as to allow them to remain beneath the 

 water for a considerable space of time. This structure 

 we shall presently examine in greater detail. 



As the method of respiration effectually disproves 

 the general notion that whales should be ranked among 

 the fishes, there is little difficulty in placing them in 

 their true position. The structure of the heart, which 

 possesses two auricles and two ventricles, whereas the 

 fishes only possess one of each, and the fact that the 

 young are nurtured by the mother's milk, are proofs 

 amply sufficient to determine their true situation to be 

 among the mammalia. 



In few animals do we find the structure more 

 curiously modified to suit the conditions of existence 

 than is the case with the whales. Passing the whole of 

 their life in the water, their form, like that of the fish, 

 is that best adapted for passing through their native 

 element ; the organs of locomotion, however, are of a 

 different nature. 



The fore-limbs, until stripped of their covering, 

 closely resemble the fins of a fish. They are, however, 

 of little use in forcing the animal through the water, 

 their chief duty lying in preserving the equilibrium of 

 the body and in clasping their young. The hinder 

 limbs are not developed, being visible merely as small 

 and imperfect bones when the skeleton is examined. 

 In fact, they can scarcely be said to exist at all, and the 

 very pelvis is only a slight rudimentary process, not 

 attached to the spine. 



The great organ of locomotion is found in the tail, 

 which is set transversely with the body, and is usually 

 of very great comparative size. In a whale of ordinary 

 dimensions, the tail, though only a few feet long, would 



