THE OPOSSUM 



61 



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

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

 echidna. 



FIG. 17. 



THE ORMTHORHYNCHUS. 



But these two animals differ from all other beasts in 

 so many and such important points that they almost 

 foim a sort of zoological half-way house between birds 



