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ANNALS NEW YORK ACADEMY OF SCIENCES 



these regions. The EanidgR, like the Bufonidae, represent a less ancient 

 dispersal, probably from a southern Palsearctic or Oriental center, since 

 they have reached northern Australia on one side and northwestern South 

 America on the other, and, while they have reached Madagascar and the 

 Solomon Islands, they have failed to reach the Antilles. 



These suggested lines of dispersal are based upon the present distribu- 

 tion interpreted in accord with the principle'fe outlined in previous pages 

 of this article. While the past liistory of the Amphibia is too little known 



Ci/s/igna thidde. 



FiG. 33. — Distribution of three families of Anura 



These may be interpreted as due to three successive dispersals from the north. The 

 other families of frogs and toads are more widely spread, and their regional abundance 

 has conditioned certain peculiarities in the distributions here sliown. 



to confirm them liy adequate direct evidence, I believe that good infer- 

 ential evidence might be obtained from a comparison of the progressive 

 or archaic characters of the skeleton in the different families. The fossil 

 Amphibia afford sufficient evidence to determine the broader lines of their 

 evolution and differentiation, although they tell very little about their 

 past distribution. The same conditions liold true with regard to the 

 fresh-water fishes. 



