228 The American Geologist. 
October, 1005 
b. Orders not certainly known in Basal Eocene but 
probably belonging to this radiation. 
Insectivora, giving rise to modern Insectivora. 
Lemuroidea. 
Rodentia, Not yet certainly known earlier than Middle 
Eocene. 
IV. — Second or Higher placental radiation (= Ceneutheria Osborn), 
Middle Eocene and Tertiary. 
A. Chief centres North America and Eurasia, migrating to 
Africa and South America. 
a. Orders derived from first placental radiation. 
Edentata from Radiation III (North America only). 
Insectivora from Radiation I and III. 
Rodentia. 
b. Orders characteristic ot second placental radiation. 
Cheiroptera. 
Carnivora (Fissipedia and Pinnipedia). 
Primates, Anthropoidea, possibly from Radiation III. 
Perissodactyla, Lower Eocene. 
Artiodactyla, Middle Eocene. 
c. Centres of origin unknown. 
Nomarthra or Effodientia (Lower Oligocene of France, 
Necromanis Filhol.) 
Tubulidentata (First appearing in Lower Oligocene of 
France, Palseorycteropus Filhol). 
B. Chief centre Africa, migrating in upper Oligocene 
(Sirenia), lower Miocene (Proboscidea), and Pliocene 
(Hyracoidea) to Europe, to Asia (Hyracoidea). Also 
to North and South America (Proboscidea). 
firenia, Middle and Upper Eocene. 
Proboscidea, Middle Eocene. 
Hyracoidea, Upper Eocene. . 
Arsinoitherium. 
Barytherium. 
C. Chief centre South America. 
a. Autocthonous orders. 
Litopterna. 
Toxodontia. 
Typotheria. 
Astrapotheria. 
Pyrotheria. 
b. Autocthonous or derived orders, in part. 
Edentata, Suborders: Lorigata (Giyptodontia and Dasy- 
poda), Pilosa (Gravigrada, Tardigrada, Vermilingua). 
