VARIATION IN HEAD LENGTH OF SPERMATOZOA 



507 



and the other at 27.8 //, givmg a ratio of 1.00 : 1.09. The majority 

 of the individuals are grouped around the higher mode. If these 

 modes can be considered as related to the sex chromosomes the 



27.1 



29,5 



27,1 



29.5 



Fig. 1 Corizus lateralus; frequency distribution of head-lengths of 500 sper- 

 matozoa from a single testis. 



23.3 23.7 24.0 24.4 24.7 25.0 25.4 25.7 26.1 

 8 10 13 13 11 13 14 16 19 



Value in 23.0 



Frequency 7 



26.4 

 23 



29.8 



28 



26.7 

 27 



30.1 

 20 



27.1 

 42 



27.4 

 30 



1.8 

 15 



30.5 30.9 31.2 



17 



11 



10 



28.1 

 11 



31.6 



8 



28.4 

 13 



31.9 

 6 



28.8 

 19 



29.1 

 26 



29.5 

 38 



32.3 32.6 

 9 5 



Fig. 2 Corizus lateralus; frequency distribution of head-lengths of another 

 sample of 500 spermatozoa from the same testis as those given in figure 1. 



Value in 23.0 23.3 23.7 24.0 24.4 24.7 25.0 25.4 25.7 26.1 



Frequency 4 6 7 7 5 7 11 11 11 13 



26.4 26.7 27.1 27.4 27.8 28.1 28.4 28.8 29.1 29.5 

 20 27 54 32 20 21 17 19 28 45 



29.8 30.1 30.5 30.9 31.2 31.6 31.9 32.3 32.6 

 30 15 12 10 7 8 4 5 5 



