CETACEA : BAL^ENID^E. *J I 



mouth is spouted to a great height. The species are 

 numerous. 



Those naturalists who, like Dr. Gill and others, regard 

 the Cetacea as a distinct order, divide the group into two 

 sub-orders : the Mysticete or Whalebone Whales, which 

 have no true teeth in the adult state, (teeth are present 

 in the unborn young !) but which have whalebone devel- 

 oped from the upper jaw ; and the Denticete or Toothed 

 Cetaceans, which have teeth but have no development of 

 whalebone. There are several distinct families in each 

 group, some of which will now be briefly described.* 



BAL^NID^:, OR RIGHT-WHALE FAMILY. This Fam- 

 ily comprises Whales which have no real teeth, but the 

 two sides of their upper jaw, which is keel-shaped, are 

 furnished with rows of vertical horny plates, called whale- 

 bone, formed of a sort of fibrous horn, and which are 

 fringed on their inner edges. This arrangement is adapt- 

 ed to the nature of the food of these whales, which con- 

 sists of small marine zoophytes, mollusks, and crustaceans. 

 Fig. 5 8. Swimming through schools of 



these little animals, the Whale 

 engulfs myriads of them at 

 once in its enormous mouth ; 

 and the water taken with them 

 is strained off through the 

 .fringes, and all the animals, 

 skuii of Right whaie, showing the even ^e smallest, retained and 



whalebone. Swallowed. 



The Genus Balcena comprises the Right Whales proper 



* Including the Zeuglodonts (fossil), Gill recognizes three sub-orders and nine families, 

 viz. : 



Denticete ( Platanistidaj, 



Zeuglodontia or / Basilosaurida;, , or , IT . Delphinidas, 



Zeuglodonts. \ Cynorcida?. Toothed Whales, 4 Ziphiidse, 



as the Sperm | Physeteridae, 

 Whales, &c. ( Rhabdosteidx. 

 Mysticete or ( Balsenopteridae, 

 Whalebone Whales. \ Bahenid*. 



