202 THE AMERICAN NATURALIST. [Vol. XXXVI 



Table I. Measurements of eight" brothers and sisters i, 

 days after hatching. 



Ten other young from various females hatched about the 

 date as the above and measured October /th gave the folL 

 results, Table II. 



74 65 l\ 

 45 30 47 



f 5 1 



$ $ $\ $ 



Takmg the two tables together the largest crayfish was 62 

 mm. and the smallest 22 mm. long ; the average length was 46 

 mm. During these two months and three weeks of summer 

 some few seem not to have grown at all, while about one third of 

 them have almost doubled their length. The great difference 

 between the largest and smallest is but imperfectly represented 

 by the above figures : thus the specimens, 10 of II and i of I, 

 being in length as 31 to 1 1 seemed in bulk much more widely 

 apart and in weight they were found to be as 13 to 7. Only 5 

 of the 1 8 were females but it is not known when this preponder- 



