NATURAL HISTORY. 193 



* To his woundes worken, that with louely dart 

 Dinting his breast had bred his restlesse paine, 

 Like as tke wounded whale to shore flies from the maine.&quot; SPEXSER. 



become thoroughly tame, and are consequently less amenable to 

 the laws which accompany domestication. 



576. Sheep, however domesticated, never evince any attachment *o their keepers. 

 When food is presented tr them they come to that, hut do not heed the person who 

 is in the habit of feeding them unless the food is shown. They require the care of 

 a shepherd to conduct them, and lead the flock to where it may be wanted ; for, 

 although they keep together, the whole would wander off, and never return to the 

 fold, unless conducted. 



ORDER X. CETACEA. 



577. Why is the order Cetacea so named ? 



From the Greek word ketos, and latin cete, signifying a whale. 

 The cetaceous animals include the genera Monodon (one tooth), 

 of wkich the narwhal is an example ; Balcena, or whalebone whale ; 

 Physeter, or spermaceti whale and Delphinus, or dolphins, which 

 include the porpoise and grampus. 



578. They have no gills, but are furnished with an aperture for respiration on the 

 top of the head ; and they have a flat or horizontal tail. Their habits are in general 

 predacious, that is, they subsist by preying upon other animals. The whale tribe, 

 however, has been broadly divided into herbivorous and carnivorous cetacea. The 

 teeth of the herbivorous whales have a flat crown which determines their character. 

 These accordingly often leave the water to creep and feed upon the land, and are 

 without the distinguishing mark of the carnivorous cetaeea, namely, the singular 

 apparatus by which they cast up jets of water. 



579. Why has the order of Cetacea, been separated from the 

 classification of fishes ? 



Because, although their outward shape bears considerable 

 resemblance to the fish tribe, their anatomical conformation, 

 joined with various other characteristics, proclaim them to be true 

 aquatic mammalia. 



580. frae fishes breathe by means of gills, in which the blood is sufficient!/ acted 

 on by the air that is contained in the water around them : on the other hand, tho 

 breathe b^ means of lunys, which require to b*j filled with air from thfl 

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