57J: y AT URAL HISTORY. 



MAMMALS. 



The mammals of to-day are as sharply marked off from all other ani- 

 mals as arc the birds. With the exception of the whales and some other 

 iish-likc aquatic forms, there never has been the slightest doubt concerning 

 a single member of the group. The most superficial character, the hair, is 

 at once distinctive; for every mammal has hair, and nowhere else in the 

 whole animal kingdom do we meet with a similar protection to the body. 

 The scales of fishes and reptiles, the feathers of birds, are totally different 

 in nature and appearance. Even the whales have hair in their young 

 stages, and in some it persists even in the adults. 



Though lacking the bright plumage of the birds, the mammals have 

 their own peculiar points of interest in which they are not excelled by any 

 other animals. First, their size varies between the greatest limits; the 

 little harvest-mouse of Europe weighs scarcely more than an old-fashioned 

 copper cent, and between this and the monstrous elephants and whales 

 almost every grade can be found. In shape, too, there are many inter- 

 esting points. The long-necked giraffe, the almost neckless fish-like 

 whales, the armored armadillos, the bird-like bats, and the almost human 

 apes need only be mentioned. So, too, the mental side has its interests; 

 for here we meet with every degree of intelligence. Some are models of 

 stupidity, and, on the other hand, man is a mammal, and in him the intel- 

 lect reaches its highest development. 



The Pick-Bill and the Echidnas. 



Away down at the base of the mammals are three or four peculiar 

 forms which to the naturalist are highly interesting, from their strange 

 structure and development. All live in that land of curious animals, 

 Australia and Tasmania, some stretching over into New Guinea. Their 

 greatest peculiarity lies in their resemblance to the birds and reptiles in 

 many points of anatomy and development, while, on the other hand, they 

 arc distinctly mammalian in the rest of their anatomy. 



First, and strangest, is the duck-bill, an animal about a foot and a half 

 in length, covered with a dark brown fur, its feet webbed, its tail shaped 

 much like that of a beaver, while its head terminates not in toothed jaws 

 like an ordinary mammal, but with a bill much like that of a duck, three 

 inches long and two in breadth. At the base of the bill is a fold of skin 

 which is capable of being thrown back over the eyes. If we look at the 

 inside of the beak, we see that its resemblance is even closer to that of a 

 duck than it appeared from the surface. As will he remembered, in the 



