YERKES. 



VARIATION IN THE FIDDLER CRAB. 



433 



Among the hundreds of crabs examined not a single variation in the 

 number of joints was noticed. 



Polygon No. 7L. 



7. Propodite of great chela. Polygons No. 7R and 7L are more 

 nearly symmetrical than any of those already examined; 7R has a 

 slightly wider range of variation. 



vol. xxxvi. — 28 



