418 HAYATO ARAI 
components in order to throw some light on the growth of the 
several groups. 
The graph for the number of ova with diameters less than 20 u 
would be nearly the same as that shown by the graph for the total 
number of ova, and has therefore not been drawn. 
The form of the graph for the number of ova with diameters 
of 20 to 40 u, however, shows a slight difference. The number 
decreases rapidly from four days until twenty-three days, and 
then continues to decrease gradually till 947 days, the fluctuations 
in number being apparently due to individual variation. 
The graph for the number of ova with diameters of 40 to 60 u 
increases rapidly from twelve days and reaches its maximum at 
twenty-three days. After twenty-three days it decreases again 
at first rapidly, then more gradually. 
The graph for the number of ova with diameters more than 
60 uw shows a rapid decrease from twenty-three days to forty- 
three days. After forty-three days it shows but a very slight 
fall. It is to be noted that as the diameters of the ova increase, 
the age of their appearance advances. 
We can obtain more clearly the relative growth of these groups 
of ova from table 4, in which the total number of ova is taken 
as the standard, and the numbers of ova of various sizes are rep- 
resented as the percentages of this total. The percentage values 
of the number of ova with diameters less than 20 u range from 100 
per cent to 88 per cent of the total throughout the entire span of 
life. Within these two limits there are numerous fluctuations, 
the reasons for which will be discussed later. 
Taking the entire series from twenty days, when the largest 
follicles appear, to 559 days, the approximate age of the meno- 
pause, the average percentage values for the several classes of 
ova are— 
Under 20 » = 95.0 per cent 
20 to 40 = 2.7 per cent 
40 to 60 = 1.5 per cent 
Over 60u = 0.8 per cent 
1. Immediately after birth both the absolute number of small 
ova, as well as their percentage values, decrease rapidly, reaching 
