Ill VARIABILITY OF SPECIES IN A STATE OF NATURE 63 



virginianus are registered, we see a remarkable spreading out 

 of the spots, showing in some of the characters a tendency to 

 segregation into two or more groups of individuals, each vary- 

 ing considerably from the mean. 



In order fully to appreciate the teaching of these diagrams, 



VARIATION OF 



ICTERUS BALTIMORE. 20. 6^ 



• • • • • • 



I 



Winq. 



Tardus 





Middle Toe. 



• •• • • 



• ••• • •• • 



Hind 



••• 



•• 



Toe. 



*•:.•.. 



:; 



Bill, 



• •• 



• •• 



Bill, 



• •• • 



• •••• 



Length, 



:••:•• 



Width. 





Fig. 9. 



we must remember, that, whatever kind and amount of varia- 

 tions are exhibited by the few specimens here compared, 

 would be greatly extended and brought into symmetrical 

 form if large numbers — thousands or millions — were sub- 

 jected to the same process of measurement and registration. 

 We know, from the general law which governs variations 

 from a mean value, that with increasing numbers the range 



