348 COMPARATIVE ZOOLOGY. 



7. Cetacea, or Whales, have the form and life of Fishes, 

 yet they possess a higher organization than the preceding 

 orders. They have a broad brain, with many and deep 

 foldings; the foramen magnum of the skull is entirely 

 posterior ; the whole head is disproportionately large, and 

 the jaws greatly prolonged. The body is covered with a 

 thick, smooth skin, with a layer of fat (" blubber") under- 



Fia. 841.— Ontline of the Sperm-whale (,Phy»eter) : a, blow-hole ; 6, the case contaiD- 

 iiig spermaceti; c, jank ; d, bunch. of the ueck— betweeu it and the corner of the 

 mouth is the eye; h, hump: i, rid^e ; &, the small; /, tail, or flakes, Between 

 the dotted lines are the spiral strips of blubber. Maximum length, sixty feet. 

 South Atlantic. 



neath ; there are no clavicles ; the hind-limbs are want- 

 ing, and the front pair changed to paddles; the tail ex- 

 pands into a powerful, honzontal fin ; neck arid external 

 ears are wanting ; the eyes small, with only two lids ; the 

 nostrils ("blow-holes") — double in the Whale, single in 

 the Porpoise — are on the top of the head. All are carniv- 

 orous, and essentially marine, a few Dolphins only be- 

 ing found in the great rivers. In the Whalebone Whales, 

 the teeth are absorbed, and disappear before birth, and 

 their place is supplied by horny " baleen " plates. " The 

 Whale feeds by putting this gigantic strainer into opera- 

 tion, as it swims through the shoals of minute Mollusks, 

 Crustaceans, and Fishes, which are constantly found at the 

 surface of the sea. Opening its capacious mouth, and al- 

 lowing the sea-water, with its multitudinous tenants, to fill 

 the oral cavity; the Whale shuts the lower jaw upon the 

 baleen plates, and, straining out the water through them, 

 swallows the prey stranded upon its vast tongue." In tlie 



