ORDER VI. THE CETACEA. 239 



pouriiio; it inti) tlic general circulation, as it is required, and thus, for a time, 

 superseding the necessity ot" respiration. 



The anatomy of their jiectoral fins bears a great resemblance to that of the 

 human arm, as the osseous structure of those organs equally consists of a 

 slioulder blade, an upper arm, a radius and ulna, and five fingers. These 

 appendages are employed to balance the animal, and to direct its course as it 

 ruslies through the water ; they also afibrd protection to its young, and the 

 female carries her cub under them, as fondly as a human mother bears her 

 child in her arms. 



But the most remarkable external feature is an immense horizontal tail, of 

 prodigious power, by which even the most gigantic varieties are able to force 

 themselves to a considerable height out of the water. Mr. Hunter observes 

 that the mode in which the tail is constructed is, perhaps, as beautiful as to 

 mechanism as any other part of the body, being principally composed of 

 three layers of tcndonous fibres. It comprises, in the larger whales, in a 

 single surface, from eighty to one hundred square feet ; its length is only 

 five or six, but its width is from eighteen to twenty-six. In its form it is 

 semi-lunar and flat ; its motions vd[)k\ and universal ; its strength iunncnse. 

 It is nearly the sole instrument of defence as well as of motion. The 

 greatest vclocitv is produced bv iiowerful strokes airainst the water, im- 

 pressed alternately upwards and downwards ; but a slower motiou is pro- 

 duced by cutting the water laterally and obliquely downwards, in a siuiilar 

 manner as a boat is forced along by a single oar in the operation of sculling. 

 So great is the speed with which they move, that they have been very appro- 

 priately denominated the birds of the sea. 



The head is of enormous size, forming about one third of the whole body ; 

 the mouth, when open, is as large as the cabin of a ship; instead of teeth, 

 it is furnished witli ab(.)ut five hundred lamina- of whalebone, ranged side liy 

 side, two thirds of an inch apart, and resembling a frame of saws in a. saw- 

 mill. Tlieir internal edges are covered with fringes of hair ; externally they 

 are curved and flattened down, so as to present a smooth surface to the 

 lips. In addition to these, there are suspended from the palate many other 

 small lamin;v3 of the thickness of a quill, a few inches long, likewise termi- 

 nating in a fringe. Thus the whole roof of the mouth seems lined with 

 shaggy fur, under which lies the soft, spongy, and non-projectile tongue, 

 often ten feet broad, and eighteen feet long. This strangely furnished organ 

 is most beautifully adapted as a means of procuring the peculiar food on 

 which the animal subsists. This consists of very minute animals, of the 

 Medusa kind, with which its pasture-grounds, as they are termed, in the 

 northern seas abound. In getting its food, the whale moves ra[)idly through 

 the ocean with open mouth, and catches millions of these little creatures in 



