74 
(1.) Anterior region, 10 grains contained —..._ 744 ova. 
* ss - . a aa) eee 
Middle region, zs * - oe | ee 
73 53 3 . ee / 2) ee 
Posterior region, ,, *5 is > SO 
5 a Fr af x 2 ee 
Average for 10 grains = 1732 ova. 
(2.) Anterior ventral region, 10 grains contained 804 ova. 
is * = ay i = 189 
Anterior ventral lobe, e I Fe Soaueee 
2 ss 55 a - ws STO ees 
Middle region, a A As ra Sig 
5 Esc = a Soi ss 
Posterior region, —... a be rs SSOnae- 
Average for 10 grains = 838 ova. 
The differences in number of the ova in the various 
samples were due chiefly to the mixture in various pro- 
portions of eggs of slightly different size, and also to the 
varying admixture of water and connective tissue —both 
sources of error which are unavoidable in this method of 
investigation. ‘Two kinds of ova are present im the roe of 
the plaice, (1) large ova lightly attached or lying freely 
in the lumen of the ovary, and smaller immature oya still 
adherent to the epithelium. In fish (2) which had not 
begun to spawn, I counted 492 large mature ova in one 
ovary; their diameter was 1:32 mm. Nearly all the 
remaining ova were about 1 mm. in diameter, and there 
were few intermediate in size. ‘This is in accord with the 
general belhef that the process of ripening, or the absorp- 
tion of fluid by the ova, is very rapid. Fish (1) had just 
begun to spawn, but a similar contrast between mature 
and immature ova was evident. 
