ii4 VERTEBRATES: MAMMALS. 



The Genus PJwccena Porpoises and Grampuses is 

 distinguished from the Dolphins proper by a short and 

 convex muzzle. The members of this genus are from 

 four to twenty feet in length, and, like dolphins, are often 

 seen in large herds. 



The Common Porpoise, D. pJioccena, Linn., is the small- 

 est of the Cetaceans, being only four or five feet long ; 

 the color blackish above, whitish below. 



The Grampus or Killer, D. orca, Cuv., is twenty to 

 twenty-five feet long, and is said to attack the whale. 



The Blackfish or Round-headed Grampus, D. globiceps, 

 Cuv., is twenty feet long ; shining bluish-black above, 

 lighter below. 



The White Grampus or White Whale, D. leucus, Gm., 

 Beluga borcalis, Lesson, of the Northern regions, is ten 

 to twenty or more feet in length, with the dorsal fin small, 



Fig. 85. 



White Whale, D. leucus, Gm. 



and for a Cetacean with an unusually distinct neck, the 

 vertebrae of which are separate, and move freely upon one 

 another. It often ascends rivers for a considerable dis- 

 tance, and is common in the St. Lawrence. A specimen 

 of this animal, about ten feet long, and weighing about 

 seven hundred pounds, was kept in a tank in the Aqua- 

 rial Gardens, Boston, for about two years. He was quite 

 docile, learned to recognize his keeper, and would come 

 and take food from his hand. He was trained to the har- 

 ness, and drew a young lady in a car prepared for the 

 purpose. 



The Genus Monodon Narwhal has no true teeth, 



