GERM CELLS OF ANURANS 271 
Some of these vesicles are of exceedingly large size in the prim- 
ary spermatogonia, and represent possibly, two or more individual 
vesicles pressed so tightly together as to appear as a single vesicle. 
At times the individuality of the larger number of vesicles is 
obscured or may disappear altogether, not to appear again until 
the early prophase of the succeeding division when the chromo- 
somes reform within the vesicles. Figures 1 and 2 give a good idea 
of the enormous size attained by these vesicles in certain cells. 
The combined size of the vesicles is so great that the nucleus com- 
pletely fills the cytoplasm except for a narrow peripheral border. 
These chromosomal vesicles are the means by which the indi- 
viduality of the chromosomes is maintained from cell generation 
to cell generation. During the so-called 'resting' stages of the 
cell, when the chromosomes appear to have lost their identity, 
and merged with the other elements of the nucleoplasm, they are 
in reality diffused within little sacs or vesicles, and probably 
thus remain entirely separated from one another throughout this 
diffuse period. No one nowadays seriously maintains that 
chromosomes maintain a strict morphological identity, i.e., ap- 
pearance, throughout all stages of cell life, but that they do main- 
tain a genetic continuity or individuality throughout 'resting' 
stages of cellular life by means of chromosomal vesicles cannot be 
seriously questioned. 
The chromosomes that arise from chromosomal vesicles during 
prophase stages of mitosis are the same chromosomes that went 
into them during the telophase of the preceding division. The 
writer can speak only for the conditions presented bj'' the frog, 
but the accounts in the literature indicate that this statement 
probably holds true for a great many forms, possibly all. The fact 
that such chromosomal vesicles have not been found in certain 
groups, as for instance, coelenterates, according to G. T. Hargitt 
('20), is no sure indication they do not exist in that group. 
