No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 
this peripheral part of the nucleus, which may be radially dis¬ 
posed or else form a loose network. The size of the granules, 
their abundance and staining intensity vary in different nuclei 
of the same size, and there is no sharp distinction between the 
smallest nucleoli and the largest of these granules. In this 
species, as in the preceding, I was unable to detect any sub¬ 
stance which stained like chromatin. 
I have been unable to determine the origin and ultimate fate 
of these nucleoli, owing to lack of material ; but a few justifi¬ 
able conclusions may be drawn from the facts at hand. Thus 
the number and size of the nucleoli stand, as a rule, in a direct 
ratio to the size of the nucleus. Further, those irregularly lobular 
nucleoli described above probably represent amoeboid changes 
of the nucleolus, such as have been seen in life by previous 
investigators, though it is strange that these nucleoli differ from 
all others in consisting of a single substance and in containing 
no vacuoles. Lastly, the number and size of the vacuoles 
increase, as a rule, with the size of the nucleus. 
It is worthy of mention that usually there are a larger num¬ 
ber of very small nucleoli in the larger nuclei than there are 
in the smaller nuclei, although the largest nucleoli of the 
former are much larger than the largest nucleoli of the latter 
nuclei. We must conclude, then, that though the size of the 
nucleoli increases as a rule with that of the nucleus, new 
nucleoli are also being formed as the nucleus grows larger. 
Now some of these new small nucleoli found in the largest 
nuclei have undoubtedly been produced by division from some 
of the larger ones : thus I have frequently observed irregular 
(amoeboid) nucleoli with oval prolongations, or with small 
nucleoli closely apposed to their surfaces, and it probably is 
correct to conclude that such small nucleoli are in process of 
division from the larger ones (Figs. 23, 25, 27, 28, 33). 
Whether all the small nucleoli of the larger nuclei have 
had such a formation is difficult to determine, since in some 
of the largest nuclei most of the smallest nucleoli may be 
peripheral in position, close to the nuclear membrane, and 
far removed from the larger nucleoli, so that it might seem 
that the substance of these was extranuclcar in origin. The 
