110 ON THE STRUCTURES AND DISTRIBUTION OF THE 



trachia, Pleurodire Tortoises, its Elapid venomous snakes, and the whole Flora, 

 according to Unger. 



K. Neo tropica. — Marsupial 'and Edentate Mammalia, Inferior Eodentia and 

 Quadrumana, Pleurodire Tortoises, Pleurodont Lacertilia, Arciferous Batrachia, 

 Clamatorial and PuUastriform Birds, Characin and Erythrinid Malacopterigii. 



K. Nearctica. — Lacking most of the inferior types of the preceding, it retains 

 more Arcifera and Bufoniformia, Pleurodont Lacertilia, and Clamatores, than 

 the following ; possesses the inferior Urodela, the Aphredoderus and Percopsis, 

 and wants as types of the 



R. Pal ae arcti ca. — Higher Urodela, Acrodont Lacertilia, higher Gallinte* and 

 Oscines. This is inferior, however, to the last in Ophidia Solenoglypha. 



R. Palaeotropicaor Lidica, — Superior in types of Teleostei, Batrachia Anura, 

 Lacertilia Acrodonta, Testudinata,t Gallinaceous and Oscine Aves, Mammalia, 

 including Homo. 



If the above succession be marked out in present time, it has no doubt existed 

 throughout a longer or more probably shorter series of recent geologic periods or 

 epochs, and over areas of course only partially coinciding witli those of the present 

 Regions. This points to the Regio Palteotropica, faunally and florally most advanced 

 in time, as the seat of first origin of the human species, as already indicated by revela- 

 tion and tradition. The fact of its being the source of such a majority of the vegeta- 

 ble and animal products most useful to the species, is in harmony with this view ; 

 and more so is the known, almost regular departure from the typical symmetry of 

 form and expression of mind by body, in the men of the different Regions. That these 

 areas were occupied by man in this succession, determined by their preparation for 

 maintaining a degree of developmental perfection, sufficient to enable him to take his 

 part in " the struggle for existence," is a natural sequence of the relation in time. 



Palseontology is as yet too incomplete to answer the question as to how ancient 

 such a relation may be. Its indications are quite contradictory, and perhaps may 

 not be relevant, prior to Cfenozoic time. 



Thus the resemblance between existing Australian and American types and terti- 

 ary European! forms successively, harmonizes with the existent relations between 

 the faunae here proposed ; but the similarity between fresh water shells of the Upper 

 Missouri Lignite and recent Indian forms, between American Eocene and European 



* E. g., Phasianns, Tetrao, Lyrurus, Tetraogallus, etc. 



t Possesses a greater number of distinct types of Eraydidas and Testudinida; than the R. Nearctica, though 

 not much beyond it. 



X Among others, the extinct genera Polysemia J/yj'. and Heliarchou Myr. e.vhibit the unossified carpus and 

 tarsus of the recent American Plethodonlida?. 



