The relative breadth of carapace and of tail segments in the 

 male and female may be more clearly shown by expressing 

 them in the number of times they were contained in the 

 length of the carapace, thus : — 



These figures show that the breadth of the carapace is 

 contained 1-48 times in its length in the case of the female 

 and I '43 in the case of the male : that is, that the carapace 

 of the female is relatively narrower than that of the male. 

 In the case of the first segment its breadth is contained in 

 the length of the carapace 1 76 times in the female and 2 -03 

 in the male, a difference of -27. This first segment is, there- 

 fore, narrower in the male and this is true also of the succeeding 

 segments, the relative difference being expressed by the figures 

 39, 48, 46, 37, 27. This may be expressed in another and more 

 direct way by taking the length of the carapace as 100 and 



[c.p. 5-13.] ° 



