24 



THE MAMMALIA 



[SECT. A 



CLASSIFICATION (Parker and Haswell): 



CLASS MAMMALIA. 



Sub- Class 1. Prototheria. 



Order Monotremata. 

 Sub- Class 2. Theria. 



Section A. Metatheria. 



Order 1. Polyprotodontia. 

 Order 2. Dipro-todontia. 



Section B. Euiheria. 



Order 1. Edentata. 



Order 2. Cetacea. 



Order 3. Sirenia. 



Order 4. Ungulata. 



Order 5. Carnivora. 



Order 6. Rodentia. 



Order 7. Insectivora. 



Order 8. Cheiroptera. 



Order 9. Primates. 



While the system of classification thus set forth may be retained on 

 account of its simplicity, the results of recent work shew that in several 

 respects, it fails to represent correctly the relations indicated by the actual 

 structure of the animals concerned. Speaking generally, all the amended 

 classifications are more complicated. In some of them the attempt is made 

 to arrange the several Orders of the Eutheria in groups, though only so far 

 as is warranted by the facts. The scheme (Fig. 11) published by Gregory 

 (1910) is relevant, since it exhibits relationships based upon discoveries of 

 extinct mammals. Through these extinct forms, some existing Orders be- 

 come associated. Other living Orders {e.g. Ungulata) are shewn to include 

 subdivisions (Artiodactyla and Perissodactyla) of diverse origin. 



