THE OPOSSUM 



6i 



other beasts. Nevertheless, it is now certain that it truly 

 lays eggs, and that the same is the case with the 



echidna. 



Fig. 17. 









:■ '>-"nV"'''.\^v'>}:v'/':::- '^^ 



THE ORNITHORHYNCHUS. 



But these two animals differ from all other beasts in 

 so many and such important points that they almost 

 form a sort of zoological half-way house between birds 



