348 
COMPARATIVE ZOOLOGY. 
1. 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- 
Fig. 341.—Outline of the Sperm-whale ( Physeter) : a, blow-hole ; 5, the case contain¬ 
ing spermaceti; c , junk ; d , bunch of the neck—between it and the corner of the 
mouth is the eye; k, hump; i , ridge ; Jc , the small; /, tail, or flukes. 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, horizontal fin; neck and 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 66 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 r upon the 
baleen plates, and, straining out the w T ater through them, 
swallows the prey stranded upon its vast tongue.” In the 
