120 BIOMETRY 



as are very seldom made use of by systematists for 

 the distinction of natural species. 



BIBLIOGRAPHY. 



GALTON, F. : Natural Inheritance, 1889. 



PEARSON, K. : The Grammar of Science, second edition, 1900. 



VERNON, H. M. : Variation in Animals and Plants, 1903. 



DAVENPORT, C. B. : Statistical Methods, 1904. 



BIOMETRIKA, 1901 



JOHANNSEN, W. : Ueber Erblichkeit in Populationen und in 



reinen Linien, 1903. 



Elcmente der Exakten Erblichkeitslehre, 



1909. 



