210 
Katharine Foot and E. C. Strobell 
and 50. Tliose who are familiär with tlie clrromatin nucleolus figured for 
the spermatocytes of so many forms must admit that there is a striking 
resemblance between many of these spermatocyte nucleoli, and those we 
have demonstrated in several of the ovarian nuclei of our plates XVI and 
XVII. Again this structure in Protenor Supports Buchxer’s observations 
as to its great variability of form — although most frequently it is a 
single bodv this feature is by no means constant eitlier in the ovary or the 
testis. Protenor further Supports Buchxer’s observations as to the pres- 
ence of the stage demonstrated in our photo 51 — compare this photo 
with Buchxer’s (1909) figures 101 and 103 — compare further our 
photo 44 with Buchxer’s figure 100. 
Wentwarter and Sainmont (1908) made the important discovery 
that in the ovary of the cat a chromatin nucleolus is present having many 
features in common with the chromatin nucleolus of insects. It is present 
not only in the oögonia but also in the oöcvtes and what is of special 
interest it appears as a single body not only before but also during mitosis. 
In the oögonial divisions it most frequently lags in division but finally 
divides as a monosome. «Dans la plupart des figures de diaster, on con- 
state un element reste en arriere, dont la Separation en chromosomes- 
filles n’est pas encore effectuee» (fig. 17). 
Further the chromatin nucleolus shows great variability in form und 
size, whereas the true nucleolus which is also present at these stages 
remains less variable, p. 203: «Le nucleole ne varie guere, mais l’autre 
element intranucleaire atteint parfois des dimensions colossales, temoin 
la fig. 27. » 
These authors give a brief summary of their observations as follows, 
p. 234: «Quant ä l’autre element que, jusqu’ä present, nous avons compris 
dans Fappareil nucleolaire, il offre des caracteres tres differents du nu- 
cleole vrai et une evolution tout a fait speciale. 
Dans les oogonies au repos, on ne le distingue pas; mais lorsque 
le noyau s’apprete ä la mitose, avant meme que le spireme ne soit edifie, 
on le remarque sous la forme d’un corps allonge, divise le plus souvent 
suivant sa longueur (fig. 3). II est toujours colore en bleu fonce, comme 
la chromatine. Plus tard, il est moins facile ä reconnaitre parce que 
les c-oupes empechent de se rendre compte de la grandeur respective des 
chromosomes. Mais dans la plaque equatoriale, il y a toujours un element 
beaucoup plus volumineux que les autres et souvent recourbe en fer-ä 
cheval, alors que les autres chromosomes sont plutöt des bätonnets courts. 
On le voit aussi dans les plaques equatoriales de profil (fig. 15). Enfin, 
on constate dans la majorite des diasters, un element dont la division 
