INTRODUCTION. 



19 



natural means of obtaining food, the animals become emaciated, and at last expire. 

 The same may be said of the Delplimidce or Dolphins. 



All the Cetaceans propel themselves through the water hj the action of their 

 pectorals and caudal fin, and the individual motions of the various species are simi- 

 lar. Usually a small portion of the animal is seen rippling along as it makes its 

 respiration, then, after a few moments, settling below the surface, it again appears 

 in the same manner. When descending to the depths below, it rises a little, as in 



figure 1 ; 



then pitching headlong, "rounds out," as in figure 2; then "turning 



flukes," as in figure 3, disappears. Thus these animals wander through the track- 



less waters in their migrations ; or, when roving about at leisure on their feeding or 

 breeding grounds, they are sometimes seen in various attitudes, which will be 

 mentioned hereafter. 



