Ill VARIABILITY OF SPECIES IN A STATE OF NATURE 65 



of the clots, when even a few specimens are compared, shows 

 that the curve, with high numbers, would be a flat one like the 

 lower curve in the illustration here given. This being the case it 

 would follow that a very large proportion of the total number of 

 individuals constituting a species would diverge considerably 

 from its average condition as regards each part or organ ; and 

 as we know from the previous diagrams of variation (Figs. 1 

 to 7) that each part varies to a considerable extent, inde- 

 pendently, the materials constantly ready for natural selection 



CARDINAUS VIRGINIANUS. 58 specimens. Florida. 



Tail. 



Length 





••• 

 •••••••••• 



Wing. 



of Bird. 



•V. 



•oooo •• 



•••••e«* ••• 

 ••••e«o« 



• •o 

 >••• • 



• ••e • 



•• • 



(From Allen's Birds of Florida, p. 281) 



Fig. 12 



to act upon are abundant in quantity and very varied in kind. 

 Almost any combination of variations of distinct parts will be 

 available, where required ; and this, as w^e shall see further 

 on, obviates one of the most weighty objections which have 

 been urged against the efficiency of natural selection in pro- 

 ducing new species, genera, and higher groups. 



Variation in the Mammalia, 



Owing to the generally large size of this class of animals, 

 and the comparatively small number of naturalists who study 

 them, large series of specimens are only occasionally examined 



