No. 567] EFFECT OF DISTRIBUTION ON SPECIATION 139 



large continental islands and zoologic regions, the results 

 being shown in Table IV. The data used in this table are 



TABLE IV 



Speciation of Mammals in Various Continental Islands and Zoologic 

 Regions 



Data from Sclater and Sclater (1899) 







ImHH) 





VUff 





(22s|oOOb a q. C M.) 





Bp. 





Sp. 





Sp. 







Sp. 





Ungulates. . . 



Rodents 



Carnivores... 



Primates .... 



Elephants . . . 

 Edentates. .. 

 Marsupials . . 

 Monotremes. 



155 



106 



59 



101 



14 

 1 



.35 



19 

 3 

 6 



69 



144 

 5 



26 



36 

 3 







18 



36 

 3 



16 

 *2 



21 



12 

 11 



Totals 



685 



128 







169 



59 



9G 



37 



100 



47 



Index of mod- 



5.35 



4.12 





2.59 



2.13 



by no means up to date, being taken from the summaries 

 in Sclater and Sclater (1899), but the subsequent additions 

 to the faunas of the places concerned, and the splitting 

 up of genera and species, have probably been approxi- 

 mately proportionate in each of the five areas, and there- 

 fore the figures used are sufficiently accurate to be signifi- 

 cant. Comparing Africa, the Australian region, Australia, 

 New Guinea and Madagascar, which rank in size in the 

 order given, we find that the indices of modification of 

 their mammalian faunas are as follows: Africa 5.35, 

 Australian region 4.12, Australia 2.86, New Guinea 

 2.59, and Madagascar 2.13. Certainly these figures are 

 significant. 



Comparing the mammalian faunas of the various 

 islands of the Philippine Archipelago (Table V), we find 

 that there is even here some corroboration of our law of 



