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ANNALS NEW YORK ACADEMY OF SCIENCES 



of its species from the mainland by way of the other ishmds, it has the 

 smallest percentage of species which are not in the other Antilles. Porto 

 Eico, Hispaniola and Jamaica contrast with the Lesser Antilles (St. 

 Vincent) and Cuba in having a greater percentage of species which have 

 originated in the Antilles and been passed to each other^ but not to the 

 inainland. 



Table X gives the percentages of the species occurring in a given island 

 and also on the mainland which are fonnd in the several mainland divis- 

 ions. It is an attempt to discover the way species have moved in rela- 

 tively recent times. It probably concerns relatively recent movements 

 only, for the species have not changed enough to lead taxonomists to 

 give the mainland and insular lots different names. To be sure, we 

 know that specific identity may be preserved for long geologic time and 



Table X^^ 



S. A. only 



C. A. only 



U. S. onl'v 



S. A., C. A 



C. A., U. S 



S. A., U. S 



S. A., C. A., IT. S. 



Total S. A. 

 Total C. A. 

 Total U. S. 



Lesser 



P. R. 



Hisp. 



Cuba 



31.0 



11.6 



10.8 



3.8 



5.2 



7.0 



2 . 7 



6.3 



6.9 



7.0 



10.8 



30.0 



17.2 



14.0 



8.1 



6.3 



8.6 



2U.9 



,29 . 7 



21.3 



3.4 



7.0 



5.4 



2.5 



27.6 



32 . 6 



32.4 



30.0 



79.3 



65.1 



56.8 



42.5 



58.6 



74.4 



72.9 



63.8 



46.5 



67.4 



78.3 



83.8 



Jam. 



14.3 

 7.1 

 0.0 

 7.1 



14.3 

 0.0 



57.2 



78.6 

 85.7 

 71.4 



experimental work has indicated that a species may arise not only sud- 

 denly but in several quite independent centers. However, most of the 

 species considered here probably arose in relatively recent geologic time 

 and each in a single center. Jamaica is troublesome because 33 (all but 

 14) of the species known from there do not occur on the mainland. 

 Cuba has 51 such species ; Hispaniola, 39 ; Porto Eico, 26, and the Lesser 

 Antilles 110. 



Except for the strictly South American species in St. Vincent and the 

 strictly northern species in Cuba a large part of the species which are 

 found in the various Antilles and also on the mainland are wide ranging 

 on the mainland, being found in all three of its divisions. This may be 

 due to the greater chance tbey have of getting to the Antilles (supposing 

 they originated on the mainland) because their mainland distribution 



15 For explanation, see text. Based upon 58 species in the Lesser Antilles, 43 in Porto 

 Rico, 37 in Hispaniola, 80 in Cuba, and 14 in .Jamaica. 



