YERKES. — VARIATION IN THE FIDD ER CRAB. 



423 



IV. Results. 



1. Tables of Means, Modes, Standard Deviations, and Coefficients 



of Variability. 



Table I. contains the results of all calculations so arranged as to facili- 

 tate comparison of right and left-handed animals. The first of each pair 

 of columns gives the values for the right-handed individuals, — indicated 

 at the top by "Rights;" the second, for the left-handed, — indicated by 

 " Lefts." 



It is to be noted that no identical measurements for Rights and Lefts 

 (for sake of brevity we shall hereafter speak of the two types as Rights 

 and Lefts instead of right-handed and left-handed) are strictly comparable, 

 except frontal breadth and median length, for in every other case there 

 is marked asymmetry, and the measurements for the left side of one type 

 have to be compared with those for the right side of the other. 



TABLE II. 

 Means and Coefficients of Variability arranged for Direct 



Comparison. 



Gelasimus pugilator (Males). 



Frontal breadth 



Median length 



Lateral margin, great chelar side . . 

 Lateral margin, small chelar side . . 



Meropodite of great chela 



Carpopodite of great chela .... 



Propodite of great chela 



Meropodite of small chela 



Carpopodite of small chela .... 



Propodite of small chela 



Meropodite of 2d leg, great chelar side 

 Meropodite of 2d leg, small chelar side 



Mean. 



Rights. 



mm. 

 15.728 

 12.245 

 8.842 

 8.400 

 8.780 

 7.115 

 9.248 

 5.563 

 3.050 

 2.710 

 7.589 

 7.127 



Lefts. 



mm. 

 15.658 



12.237 



8.716 



8.285 



8.650 



6.878 



9.038 



5.312 



2.969 



2.733 



7.523 



6.965 



Coefficient of 

 Variability. 



Rights. 



mm. 

 7.022 



7.26G 



8.845 



8.649 



9.000 



10.166 



10.215 



8.734 



9.518 



8.313 



8.479 



8.724 



Lefts. 



mm. 

 7.471 



7.598 



8.880 



9.000 



9.657 



10.472 



10.255 



9.920 



11.139 



8.898 



9.660 



9.1G0 



