1 84 



THE DARWINIAN THEORY 



in the fore foot the web extends considerably beyond 

 the fingers. In the hind foot the nails are long and 

 curved, and in the male the heel has a spur an inch 

 long, at the apex of which opens a " poison " 

 gland. 



The Ornithorhynchus is an aquatic animal living 

 in lakes and streams ; it swims and dives well, and 

 forms burrows, sometimes fifty feet long, on the banks 

 of the water in which it lives. These burrows end 



Fig. 



Echidna aculcala and Procchidna Brujnii. 



in a dilated chamber which has two openings, one 

 below, the other above the water level ; in this 

 chamber the animal rolls itself up into a ball when 

 going to sleep. It is found in Tasmania and the 

 southern and eastern parts of Australia. 



Echidna, the spiny ant-eater (Fig. ^), is another 

 member of the group, and of this there are two 

 species found in Australia, Tasmania, and New 

 Guinea. Its length is from a foot to 18 inches 

 or more. It is covered with fur intermixed with 



