90 TYPES OF ANIMAL LIFE 



whale, and the foot of the horse. But in birds, the hind 

 limbs are always " walking " legs, and fore limbs " wings," 

 although, as in the ostrich and the apteryx, they may be 

 incapable of flight. They are always, that is to say, 

 formed on the type of the flying wing, even when they 

 cannot sustain or propel the body in the air. We see 

 this emphatically in the penguin, a bird incapable of so 

 rising, but a most wonderful swimmer beneath the sur- 

 face of the sea. There it propels itself by the aid of its 

 fore limbs, which are worked powerfully by enormous 

 muscles, so that the bird may be said to fly under water. 

 Very many beasts and reptiles have long tails, and some 

 have none, but eveiy existing bird has its tail feathers 

 supported by a short structure of flesh and bone. 



Most beasts have a hairy coat, and a few are naked, 

 while some, as the pangolin and armadillo, are clothed 

 with scales or bones, and much diversity exists in the 

 covering of reptiles. But all birds are, as before said, 

 clad with feathers as to their body and with scales as to 

 their feet. Almost all beasts and reptiles have teeth in 

 their mouths, though a few, like the ant-eaters, turtles, 

 and terrapins, have none. But no existing bird has 

 teeth, whUe all have their jaws clothed with that horny 

 investment we call the bill. 



We have, however, compared the class of birds with 

 extinct as well as with living reptiles, and, therefore, we 

 cannot fully comprehend what the class of birds is, nor 

 what the turkey's profoundest relations to other crea- 

 tures are, if we take no account whatever of birds which 

 have passed away. And very many a bird has here and 

 there passed away which was known to a few preceding 

 generations of mankind, if not to our own fathers. 



Thus, that handsome bird, the great bustard, was not 

 so long ago abundant in the more open parts of England 



