SURVEY OP THE ORDERS OF MAMMALIA. 739 



" Cenoplacentalia," which made, so to speak, a fresh start, with a 

 premium on brains, and led to most of the modern types. In almost 

 every case, it may be said that an order begins with small repre- 

 sentatives, and that the giant forms almost always indicate the end 

 of a race. 



SYSTEMATIC SURVEY OF THE ORDERS OF MAMMALIA 



I. Sub-class PROTOTHERIA or ORNITHODELPHIA, Orders 

 Monotremata, and (?) Allotheria or 

 Multituberculata. 



II. METATHERIA or DIDELPHIA, Orders Poly- 

 protodontia and Diprotodontia. 



III. EUTHERIA Or MONODELPHIA. 



Orders of EUTHERIA. 



1. Xenarthra. 1 u 



2. Nomarthra. / 



3. Sirenia. 



4. Ungulata. 



Edentates." 



Hyracoidea. 

 Proboscidea. 

 Extinct sub-orders. 



5. Cetacea. 



Mystacoceti baleen cetaceans. 

 Archceoceti (extinct types). 

 Odontoceti toothed cetaceans. 



6. Rodentia. 



Simplicidentata. 

 Duplicidentata. 



7. Carnivora. 



8. Pinnipedia. 



9. Insectivora. 



10. Galeopithecidse or Dermaptera. 



11. Chiroptera. 



Megachiroptera. 

 Microchiroptera. 



12. Prosimice or Lemuroidea. ) =primates 



13. Anthropoidea. J 

 49 



