CORRELATION AND VARIATION IN INTERNAL AND 

 EXTERNAL CHARACTERS IN THE COMMON TOAD 

 (BUFO LENTIGINOSUS AMERICANUS, Le C.) 



BY 



WM. E. KELLICOTT, Ph.D. 



W.TH Six Figures and Twenty-two Tables 



I Introduction 575 



II Summary 57^ 



III The data 577 



1 Material 577 



2 Methods 578 



1, Numerical ratio between the sexes 580 



4 Variability 580 



5 Correlation 587 



IV General discussion of the data 597 



1 Numerical ratio between the sexes 597 



2 Variability 600 



a Comparative variability of the sexes 600 



b The frequency polygons 601 



c Comparative variability of external and internal characters 601 



3 Correlation 607 



a Comparative correlation of the sexes 607 



b Comparative correlation of external and internal characters 608 



V Literature cited 612 



I INTRODUCTION 



The present study was undertaken with a view toward getting 

 information first as to the degrees of correlation and variabihty of 

 internal characters, such as the viscera and muscles, regarding 

 which our knowledge is remarkably deficient, and second as to 

 the general condition of correlation among a considerable number 

 of characters in a single group of individuals. It has been pointed 

 out frequently that selection acts not upon single characters or 

 variations alone, nor as such, but upon the entire organism as the 

 unit: that there results from this action a "balance of fitness" 



The Journ.al of E.xperi.mental Zoology, vol. iv, no. 4. 



