416 FOUB-FOOTED AMEBIC AN S 



ORDER OF WHALES, PORPOISES, DOLPHINS 

 Cetacea 



(From Cetus and Ketos, the Latin and Greek words for 

 Whale, — Whale meaning roller.) All of this order live on 

 animal food and are helpless on land. One species, the 

 Killer Whale, eats other warm-blooded animals. 



Family of True Whales 

 Balaenidse 



(Number of North American Species, Seventeen) 



Has plates of baleen, the horny fibre known as whale- 

 bone, growing from its palate. Feeds on Sea mollusks. 



Bowhead Whale Ba/cena mysticetus. 



Length, 45—30 feet. 



Finback Whale Ba/cenoptera muscu/us. 



Length, 65-70 feet. 



Family of Sperm Whales 

 Physeteridae 



(Number of North American Species, Two) 



This family lives on squids and cuttlefish, among other 

 things. It yields the perfume called ambergris. Sperma- 

 ceti, a lardy substance used in making candles, is found in 

 a great cavity in the skull. The fat blubber, which covers 

 the body under the skin, making it easy for the Whale to 

 float, yields sperm oil. 



Cachelot, or Common Sperm Whale . Physeter macrocepha/us. 

 Length, 55-60 feet. 



Family of Dolphins 

 Delphinidas 



(Number of North American Species, Twenty-eight) 



Common Porpoise Phocoena phoccBna. 



Length, 4| feet. 



