132 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



Bateson does mention (p. 63) substantive variation in the joints of the 

 leg of the cockroach (Blatta americana), but only in its relation to the 

 Dumber of joints, no lighl being thrown upon <>nr problem. 



In case of the series of joints of the crab leg it would seem probable 

 that the distal would be the most variable, since they are most likely to 

 be modified by the use of the leg. 



For convenience of comparation the Coefficients of Variablity of 

 the measurements taken on the chelar joints are here repeated (see 

 Table [L 



Meropodite of greal chela, 

 Carpopodite of great chela, 

 Propodite of greal chela, 

 Meropodite of small chela, 

 ( larpopodite of small chela, 

 Propodite of small chela, 



Rights. 



9.000 

 10.166 



Ki.215 



8.7;; i 

 9.518 

 8.313 



Lefts. 



9.657 

 10.472 



10.255 

 9.920 



11.139 

 8.898 



Only for the greal chela of the Rights is there a constant increase in 

 variability from the proximal to the distal joint. In every case, how- 

 ever, the carpopodite is much more variable than the meropodite. 



POLTOOH N" 7B 



