238 PALEONTOLOGY 



CLASS: MAMMALIA. 



SUB-CLASS : Prototheria (egg-laying mammals). 



ORDER i. MULTITUBERCULATA (known only by lower 

 jaws and teeth), Trias. -Eocene. 



2. MONOTRE.MATA (the egg-laying mammals of 

 Australia), Plio.-Rec. 



SUB-CLASS : Metatheria (pouched mammals). 



ORDER. MARSUPIALIA (now confined to Australasia and 

 South America), Jur.-Rec. 



SUB-CLASS. Eutheria (placental mammals). 



SUPER-ORDER i. UNGUICULATA (clawed mammals, 

 including the most primitive Eutheria, Insectivores and 

 Rodents, the Carnivora, and the two highly specialized 

 orders, the Edentates and the Bats), Eoc.-Rec. 



2. UNGULATA (hoofed mammals, divided by Osborn 

 according to their geographical origin Artiodactyla, 

 Perissodactyla, and several extinct orders being Hoi- 

 arctic,* Proboscidea, Hyracoidea, Sirenia [sea-cows], and 

 some extinct orders African, while a number of extinct 

 orders are South American). 



3. PRIMATES (lemurs, monkeys, and man), Eoc.-Rec. 



4. CETACEA (whales and dolphins, derived from primi- 

 tive carnivores), Eoc.-Rec. 



Short Bibliography. 



AGASSIZ, L. Recherches sur les Poissons Fossiles, 

 1833-44. 



DEAN, B. Fishes, Living and Fossil. New York, 1895. 



FLOWER, W. H., AND LYDEKKER, R. Mammals, 

 Living and Extinct. London, 1891. 



* The Holarctic Region includes the Old World north of the 

 Himalayas and the great deserts, and North America. 



