6 CETACEANS. 



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, 

 jelly-fish, and the molluscs known as pteropods. The food of many of the larger 

 species consists almost 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 

 associating together in companies known as "schools," which may sometimes 

 comprise several thousands of individuals. As a yule, 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 towards their 

 offspring. Some of the firmer 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, 

 Classification. 1 3 . . , , *!, 



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



of teeth is taken by baleen or " whalebone," and the toothed whales, characterised 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. Ktikenthal is, however, of opinion, that the whalebone and the toothed 

 whales have originated independently of one another from totally distinct groups of 

 terrestrial 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 

 particular mode of life of producing similarity in form. 



THE WHALEBONE WHALES. 

 Family BAL^NID^. 



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

 characterised 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 animals on which these whales feed from the water, the structure 

 of this being explained 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 transverse processes of the vertebrae, and having no connection 

 with the bodies of the same. The breast-bone is composed of but a single piece, 

 to which only one pair of ribs articulate. 



As remarked by Sir W. H. Flower, in the substitution of baleen for teeth, as 

 well as in the loose connection of the ribs with the backbone and the breastbone, 

 and in the reduction in the size of the latter, the whalebone whales are more 



