CETACEA. 



545 



phyodont — rthat is to say, possesses but a single set of teeth, 

 which are never replaced by others. When teeth are present, 

 they are usually conical and numerous, and they are always of 

 one kind only. 



The Cetacea may be divided into the three families of the 

 BalcRtiidce or Whalebone Whales, the Delphinida or Dolphins 

 and Porpoises, and the Catodontidm or Sperm Whales. Of 

 these, the BalcenidcR are often spoken of as the " toothless " 

 Whales, whilst the other two families are called the " toothed" 

 Whales {Odontoceti\ 



Fig. '211. — Skull of the Right Whale {^BaltEim tnysiicetus) — after Owen. 



Fam. I . Balcenidce. — The Balcsnida or Toothless Whales 

 are characterised by the total absence of teeth in the adult 

 (fig. 2ii). Teeth, however, are present in the foetal Whale, 

 but they never cut the gum. The place of teeth is supplied 

 by a number of plates of whalebone or " baleen " attached to 

 the palate; hence the name of "whalebone Whales" often 

 given to this family. They are the largest of living animals, 

 and may be divided into the two sections of the Smooth Whales, 

 in which the skin is smooth and there is no dorsal fin (as in 

 the Greenland Whale), and the Furrowed Whales, in which 

 the skin is furrowed and a dorsal fin is present (as in the so- 

 called Finner Whales and Hump-backed Whales). 



The Greenland or " Right " Whale (Balcena mysticetus) will 

 illustrate almost all the leading points of interest in the family. 

 The Greenland Whale is the animal which is sought after in 

 the whale-fishery of Europe, and hence the name of " Right " 

 Whale often applied to it. It is an inhabitant of the Arctic 

 seas, and reaches a length of from forty to sixty feet. Of this 

 enormous length, nearly one-third is made up of the head, so 

 that the eye looks as if it were placed nearly in the middle of 

 the body. The skin is completely smooth, and is destitute of 



