CHARACTERISTICS OP BIRDS. 115 



being but six or seven feet long, and on its paddles are 

 short nails, by which it can drag its unwieldy body on 

 the land to bask in the sun or to get food. All the ani- 

 mals of this tribe are like the Whales in their paddles, 

 their oily skin, their horizontally flattened tail, and their 

 fish-like shape. 



Questions. What is said of the size of animals living in water? 

 How do the Whale tribe compare in size with terrestrial animals ? 

 How do the Cetacea differ from all other Mammals ? What group 

 of Mammals are somewhat like them ? How does the tail of Whales 

 differ from that of Fishes ? What is the breadth of it ? What is 

 the chief office of the flippers ? What is said of their frame-work ? 

 What is the blubber ? What purposes does it serve ? Explain the 

 provision which enables the Whale to stay under water so long. 

 What is said of the nostrils ? Describe the spouting apparatus. 

 What are the two families of Whales ? Describe the Cachelot Whale. 

 What is said of its spermaceti? How much is obtained from one 

 Whale ? What is Ambergris ? What is said of the habits of Sperm 

 Whales? What is said of the Whalebone Whales? What are in- 

 cluded in the Dolphin family? What is said of the Porpoise? 

 What of the Dolphin? What of the Narwhal? What of the Du- 

 gong family ? What are the animals of this family commonly called ? 

 Where are they found ? What is said of the structure of the species 

 represented ? 



CHAPTER XII. 



CHARACTERISTICS- OF BIRDS. 



196. BIRDS form the second grand division of warm- 

 blooded Vertebrates. This division is separated from 

 the first division, the Mammals, by very marked charac- 

 teristics, which I will point out. 1. They are oviparous 

 (23). 2. They do not suckle their young. 3. They are 

 covered with feathers. 4. They are constructed for flight, 

 with some few exceptions. 5. They have no teeth, which 

 is true of only a few species of Mammals. 6. They have 

 bills, which is true of only one species of Mammals, the 

 Duck-billed Platypus of Australia ( 133). 7. They have 



