1 1 78 THE CETACEANS 



ered in the large rivers of the Cameroons district on the West Coast of Africa, which 

 is believed to be herbivorous, all Cetaceans are carnivorous. Their food is, how- 

 ever, very varied; and the size of the animals devoured for food bears no sort of re- 

 lation to the dimensions of their devourers. Thus, while the killer, or grampus, feeds 

 on seals and some of the smaller Cetaceans, and is indeed the only member of the 

 order which subsists on warm-blooded animals, many of the toothed Cetaceans prey 

 on fishes of various kinds, while others devour small crustaceans, jellyfish, and the 

 mollusks known as pteropods. The food of many of the larger species consists al- 

 most exclusively of squids and cuttles, and so small are the animals on which the 

 Greenland whale feeds, that it is commonly said that this species would be choked 

 if it attempted to swallow a herring. 



Although the killer is renowned for the ferocity of its disposition, 



the majority of Cetaceans are harmless and timid animals, usually as- 

 sociating together in companies known as "schools," which may sometimes com- 

 prise several thousands of individuals. As a rule, the members of a school are said 

 to display an affectionate disposition to one another; and numerous anecdotes attest 

 the strong attachment and solicitude displayed by the females toward their offspring. 

 Some of the finner whales appear to produce two young at a birth not uncommonly, 

 but the usual number is' one. 



Existing Cetaceans are divided into two great primary groups, the 



one comprising the true, or whalebone whales, in which the place of 

 teeth is taken by baleen or "whalebone," and the toothed whales, characterized by 

 the presence of functional teeth, at least in the lower jaw. These two groups differ 

 from one another in many important respects, and if they are derived from a single 

 stock, their common ancestor must have existed at a comparatively-remote epoch. 

 Dr. Kiikenthal is, however, of opinion, that the whalebone and the toothed whales 

 have originated independently of one another from totally distinct groups of ter- 

 restrial Mammals. If this view be ultimately maintained, it will be evident 

 that the Cetacean order, as at present constituted, is a heterogeneous group; while 

 we should have a most remarkable instance of the power of adaptation to a particu- 

 lar mode of life of producing similarity in form. 



THE WHALEBONE WHALES 

 Family 



The whalebone, or true whales, constitute but a single family, and are charac- 

 terized as follows. They have no teeth after birth, but the palate is furnished with 

 numerous horny plates of baleen or whalebone, which serve to strain the small ani- 

 mals on which these whales feed from the water, the structure of this being ex- 

 plained below. The skull is symmetrical, and the two branches of the lower jaw 

 are outwardly curved, and are joined at the chin only by fibrous tissue. The nostrils 

 open externally by two distinct longitudinal apertures. In the skeleton, the ribs 

 are but very loosely united with the backbone, articulating only with the horizontal 



