x A UTHOR'S PREFA CE 



The author is indebted to Miss Helen Snyder for the care 

 with which many of the drawings have been made. While the 

 drawings, except as acknowledged in the text,- have been made 

 from the specimens, suggestions as to methods of expressing 

 essential characters have been taken at times from the books 

 mentioned in the list at the end of the volume. The author 

 gratefully acknowledges his indebtedness. 



ELLIOT R. DOWNING 

 UNIVERSITY OF CHICAGO 

 SCHOOL OF EDUCATION 

 December 27, 1921 



