Ill VARIABILITY OF SPECIES IK A STATE OF XATURE 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 indi\iduals, each vary- 

 ing considerably from the mean. 



In order fully to appreciate the teaching of these diagrams, 



VARIATION OF 



ICTERUS BALTIMORE. 20. (^ 



Tdil. 



• • 



Whg. 



Tarsus 



• •• 



•• 



Middle Toe. 



• ••• ^ • • • • 



Hindi Toe. 



Bill, 



::: 



Bill. 



• •• 



Length, 



t..i.. 



Width. 



Fig. 9. 



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

 tions are exhibited by the few specimens here compared, 

 would be gTeatly extended and brought into symmetrical 

 form if large numbers — thousands or millions — Avere 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 



