CORPORA ALBICANTIA, CORPORA ABERRANTIA AND CORPORA ATRETICA 371 



A second method is to take all the corpora albicantia up to 3 cm. in diameter, and to calculate the 

 proportions in the size groups o-i, 1-2 and 2-3 cm. for each of the groups of females with 1, 2, 3, ..., 

 to over 30 corpora albicantia. The percentage composition of the 0-3 cm. groups is plotted in this way 

 in Text-fig. 18. If there is complete regression in size of the corpora albicantia one would expect, as 

 more corpora accumulate, a progressive and continued increase in the percentage of corpora in the 



": 3 - 



10 20 



NUMBER OF C ALBICANTIA 



30 >30 



Text-fig. 17. Variation in modal diameter of corpora albicantia with increasing corpora numbers. 



10 20 



NUMBER OF C. ALBICANTIA 



Text-fig. 18. Variations in percentages of corpora albicantia in different size groups, 

 with increasing corpora numbers. 



0-1 and 1-2 cm. groups, and a decrease in the proportion of 2-3 cm. corpora, until at the higher 

 corpora numbers the great majority are in the 0-1 or 1-2 cm. group. Text-fig. 18 shows that there is 

 initially a rapid decrease in the proportion of 2-3 cm. corpora and a complementary increase in the 

 proportion of 0-2 cm. corpora, but when about fifteen corpora albicantia have accumulated this change 

 in the proportions of corpora albicantia ceases, and the numbers of 0-2 and 2-3 cm. corpora are nearly 

 equal. The numbers of 0-1 cm. corpora remain small and do not show any significant increase. This 

 means, as before, that the corpora albicantia regress in size to a modal diameter of 2 cm. and then no 



