180 



BRANCH VERTEBRATA. 



PIG. 308. 



ORDER MONOTREMATA (mon o trem'a ta). 



The Monotremes (mon'o tremz), found only in Aus- 

 tralia and vicinity, form a connecting link between the 

 Birds and the Mammals. 



The Duck-bill* introduces us to the Mammals. The 

 bill of a duck is attached to the body of an otter ; while 

 the male bears on the inner side of the ankle a spur re- 

 sembling that of the domestic fowl. The fore feet have 



a web extending be- 

 yond their extremities, 

 which can be folded 

 up when the feet are 

 used for burrowing, or 

 expanded when em- 

 ployed in swimming. 

 The hind feet are 

 webbed only to the 

 base of the nails. The 

 body is covered with fur, beneath which is a layer of 

 wadding-like hair, impervious to water. Its burrow runs 

 under ground forty or fifty feet, with one entrance under 

 water, and another just above. At the farther end is a 

 nest of grass, for the rearing of its young, which are 

 hatched and cared for as in the following genus. It 

 swims upon the surface, diving frequently, like the duck, 

 and using its bill for securing its food of small insects 

 and crustaceans ; these are stored in its capacious cheek- 

 pouches, till it comes to the surface to masticate them 

 at its leisure. So far as present discoveries indicate, it 

 stands lowest in the series of mammals. 



The Porcupine Ant-eater has a bird-like head, though 



Or ni tho rhyn' chus an a tl' nus. Duck-bill. ( J.) 



* See "Fourteen Weeks in Geology," p. 173, 



