VOL. XXXVII, NO. 443 



NOVEMBER, 1903 



THE 



AMERICAN 

 NATURALIST 



A MONTHLY JOURNAL 

 DEVOTED TO THE NATURAL SCIENCES 

 IN THEIR 



^^^^Mi^^J LOTIS 1 DXrBLT5 731 



Mutation in Plants DR. D. T. MACDOUGAL 737 



Distribntion of the Fresh-Water Fishes of Mexico . . DR S. E. MEEK 771 

 Examination of Organic Remains in Postglacial Deposits 



DR. P. OLSSON-SEFIER 785 



and Literature : Exploi 



oology, A Summary of the Coccid*, Another 800 

 rext-book of Entomology, Two Papers on Insect Wings _ flora*,, A 810 



BOSTON, U. S- A. 



GINN & COMPANY, PUBLISHERS 



