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F. M. JEWELL. 



sex ratio than in the 40-100 cm. group with a sex ratio of 121.34, 

 and here again, as in all succeeding cases, the 20-30 cm. group 

 tends to lower the sex ratio for the relatively younger individuals. 

 In the 0-50 cm. and the 50-100 cm. groups there is an approximate 

 equality between the sexes, being 123.14 in the former and 123.78 

 in the latter case. The sex ratio of the groups, at which so close 

 an approximation is reached, is also practically the same as the 

 sex ratio of 123.21 for the total number of individuals. The same 

 is practically true of the 0-60 and the 60-100 groups with a sex 

 ratio of 123.46 and 122.72 respectively. In the 0-70 cm. group 

 with 797 individuals, there is a slight rise in the sex ratio (125.14) 

 and for the 70-100 cm. group with 203 individuals the ratio is 

 115.95. In the group from 0-80 cm. with 930 individuals the 

 sex ratio of 121.95 of course approaches the average and in the 

 80-100 cm. group with only 70 individuals there is a sex ratio of 

 141.37, which can, in so small a number, likewise be considered as 

 due to chance. From 0-90 cm. with 995 individuals the sex 

 ratio is 122.5 and the remaining five have a sex ratio of 400. 



FIG. i. Representing graphically the sex ratios for relatively younger and 

 older foetuses. The values for the sex ratios are indicated on the ordinate and the 

 lengths on the abscissa. The number of individuals in each case is given below 

 the lengths. Those below the dividing line (relative to length) are indicated by 

 the continuous line, those below that length by tbe dotted line. 



This is represented graphically in the following figure (Fig. i) 

 in which the foetuses below the dividing line (relative to length) 

 are shown by the continuous line. 



The values for the sex ratio are indicated on the ordinate and 



