GENERAL CHARACTERS. 5 



wide open, the upper part of the windpipe (larynx) is prolonged so as to reach the 

 opening of the nostrils in the hinder portion of the mouth, and thus form a closed 

 tube from the external nostrils to the lungs. 



As there is frequently some misconception as to the so-called 

 " spouting " or " blowing " of Cetaceans, a few words are advisable on 

 this point. When a whale comes to the surface of the water after a longer or 

 shorter period of submergence, its first act is to discharge the air from the lungs 

 previous to taking a fresh inspiration. The air is expelled from the lungs with 

 great force, and thus rises a considerable height above the surface of the water, 

 and as it is saturated with water-vapour at a high temperature the contact with 

 the cold external air at once condenses this vapour, which forms a column of steam 

 or spray. Frequently, however, a whale commences to " blow " before its nostrils 

 are actually above the surface, and then a certain amount of sea-water is forced up 

 with the column of air. 



Cetaceans include the largest animals now existing; on the <dobe ; 



A Modern Group. \ . . . 6 s ' 



and they were only approached in point of size by some 01 the 

 gigantic land reptiles which existed during the Secondary period. As a group, they 

 are comparatively modern, being unknown before the upper portion of the Eocene 

 division of the Tertiary period. In the- preceding Secondary period their place in 

 the ocean was taken by huge extinct marine reptiles, such as the ichthyosaurs and 

 plesiosaurs : but as these seem to have died out at the close of that period, while 

 ■whales are unknown in the early part of the Eocene, it would seem that there 

 was an interregnum, during which our seas were not tenanted by any large 

 animals except fishes. 



Difficulty of From their oceanic habits and huge size, the study of the larger 



observing. Cetaceans is a matter of extreme difficulty; the majority of the 

 comparatively few- specimens that are cast ashore not being seen by naturalists, 

 while even in cases where opportunity is afforded for inspection, the bodies are 

 usually more or less distorted from their proper form, while nothing can, of course, 

 be learnt as to the habits of the animals. The acquisition of such knowledge as 

 we possess of the habits and form of the larger whales has consequently been 

 acquired very slowly: but, thanks to the careful observations of several gentlemen 

 engaged in the whaling trade, we have a considerable amount of information on 

 these subjects, although there is room for much further investigation. 



Cetaceans are found in all seas, from the Equator to within the 



Arctic Circle ; and in former years even many of the larger species 

 were extraordinarily abundant in certain regions, although they have been greatly 

 reduced in numbers, and in some instances almost or completely exterminated. 

 Many of the smaller forms, known as porpoises and dolphins, ascend rivers for 

 longer or shorter distances : while some of these, as well as all the members of one 

 family are exclusively nuviatile ; the latter inhabiting the larger rivers of South 

 America and South-Eastern Asia, With the single exception of a kind of dolphin 

 recently discovered in the large rivers of the Cameruns district on the West Coast 

 of Africa, which is believed to be herbivorous, all Cetaceans are carnivorous. Their 

 food is, however, very varied; and the size of the animals devoured for food bears 

 no sort of relation to the dimensions of their devourers. Thus while the killer, or 



