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ANIMAL BIOLOGY 



prises but three genera, the duck bills (Ornithorynchus) , 

 which live in ponds and streams of Australia, the spiny 

 ant eaters (Echidna), which are found in Australia, and a 

 related genus (Proechidna) , from New Guinea. The 

 duck bills have peculiar, flattened, protruding jaws like 

 the bill of a duck, and webbed feet. The body is covered 

 with a fine fur. The eggs are laid -in burrows. The spiny 

 ant eaters have very narrow jaws; the body is armed with 

 numerous pointed spines amid the hairs, and on the lower 



FIG. 164. Echidna, the spiny ant eater. 



side of the female there is a sort of pouch in which the eggs 

 are carried, and then the young, for some time after they 

 are hatched. Aside from the habit of laying eggs, there 

 are various other features which indicate the relationship 

 of the Mohotremes to the reptiles; the group may be 

 regarded therefore as in part bridging over the gap between 

 the higher mammals and the reptile-like ancestors from 

 which they were derived. 



In the next higher order, the Marsupialia, the young are 

 brought forth alive, but in a very immature condition. 



