CETACEA. 573 



only present in a rudimentary form. There are no clavicles, 

 and some of the digits may possess more than three phalanges 

 each. Lastly, the adult is either destitute of teeth, or, 

 with the single exception of the Ztuglodontidce, is mono- 

 phyodont that 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, except in the 

 Zeuglodonts, they are always of one kind only. 



The Cetacea may be divided into the five families of the 

 Balcz?iid(z or Whalebone Whales, the Delphinida or Dolphins 

 and Porpoises, the Catodontidiz or Sperm Whales, the Rhyn- 

 choceti or Ziphioid Whales, and the Zeuglodontidce. Of these, 

 the Bal(znid(E are often spoken of as the " toothless " Whales, 

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

 (Odontoceti\ 



Fig. 244. Skull of the Right Whale (Baltena wysticetus) after Owen. 



Fam. i. Balanidcz. The Bal&nida or Toothless Whales 

 are characterised by the total absence of teeth in the adult 

 (fig. 244). 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 (Balcsna 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" 



