THE ANIMAL KINGDOM. 37 



ing the heat of the body being carried off by the water ; 

 secondly, by its elasticity it enables them to bear the 

 pressure of the water when they dive into the depths 

 of the ocean, a pressure sometimes amounting to ten 

 tons on every square inch of the enormous surface ; and 

 thirdly, the blubber being so much lighter than water, it 

 assists the huge creature in rising to the surface by buoy- 

 ing it up : this is proved by the circumstance that a dead 

 whale floats, but when deprived of its blubber the carcase 

 sinks. 



Cetacea may be divided into Carnivorous, or flesh- 

 eating, and Herbivorous, or feeding on vegetable matter. 



The Carnivorous Cetacea consist of Dolphins, Sper- 

 maceti, and Whalebone Whales. 



Dolphins have slender sharp teeth in both lower and 

 upper jaws, and are very voracious ; they may be easily dis- 

 tinguished by the peculiar shape of their head, which ter- 

 minates in a beak-like snout. They are abundant about 

 our shores, and no doubt many of you have seen the shoals 

 of them tossing about in their elegant sports. 



Porpoises differ from dolphins, chiefly from being 

 smaller, and having no prolonged snout, their muzzles being 

 comparatively short. Both of these animals follow sailing 

 vessels in herds, and pick up any sort of offal which may 

 be thrown overboard, and perform the most amusing 

 gambols. Their name is supposed to be derived from the 

 French term " Porc-poisson," or Hog-fish, for you must 

 know that formerly all the Cetacea were thought to be fishes, 

 and it was common to hear people speak of the " Whale- 

 fish;" in fact, now that we know that the Whale is a 

 Mammal and not a fish, it seems absurd that itve still 

 speak of our " whale fisheries." 



To the Dolphin tribe belongs the Narwhal, or Sea 

 Unicorn. The name Unicorn means " single horn ; " but 

 the fact is, that the spear with which the male Narwhal is 



