lECT. II.] THE DUCKBILLED PLATYPUS. 25 



LECTURE II. 



Peototheria (Monoteemata). 



The lowest, or teatless mammals, stiU linger in the 

 Australian region, in the form of the spiny Ant-eater, 

 or Echidna, and the great Water-Mole (Platypus, or 

 Ornithorhynchus). A few fossils have been found in 

 this same region, and described by Sir Eichard Owen as 



W4(E 



Fig. 2. — Young of Ornithorhynchus paradoxus, one half the 

 natural size. 



belonging to a larger species of Echidna than any of 

 the three known existing kinds. 



But in the northern world (Arctogoea) no remains of 

 any kind of Monotreme — Duckbill, or Echidna — have 

 rewarded the labour of the paleeontologist. Yet fossil 

 marsupials have long been known in this hemisphere ; 

 although, as Professor 0. C. Marsh suggests, Microlestes 

 the oldest of these — the jaws of which are found at 



