No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 301 
Rabl (’85) studied mitoses in cells of the larva of Salatnandra , 
and found that in the prophases of mitosis the nucleoli gradu¬ 
ally vanish and take part in the production of the chromatin 
threads. In the unripe germinal vesicle of Proteus , on the 
inner surface of its membrane, “ sieht man in unregelmassigen 
Abstanden von einander kugelige, stark glanzende, wie Oel- 
tropfen aussehende Korperchen,” which he assumes are neither 
nucleoli nor masses of true chromatin. 
Will (’85) studied the ovogenesis of Notonecta and Nepa. 
The young “Ooblast” contains one nucleolus bounded by a 
membrane and surrounded by smaller “ Chromatinballen” ; 
subsequently the latter bodies fuse together and form a closed 
ring around the nucleolus. The nuclear division of the ooblast 
is an amitotic one, and is preceded by a division of its nucleolus ; 
in each daughter-nucleus, then, the divided half of the primitive 
nucleolus breaks up into fragments, which become distributed 
through the nuclear sap, and the daughter-nucleus produces a 
new nucleolus without the aid of these particles. When the 
ovum proper is ripe, the nucleolus finally disappears. 
1886. 
Van Bambeke (’86) found that in the germinal vesicles of 
Aracfmida , Isopoda , Hymenoptera , and Meconema , the nucleoli 
and the chromatin do not stain with methylen green (corrobo¬ 
rating Wielowiejski) though they stain with carmine and 
haematoxylin ; “ Rien ne s’oppose, me semble-t-il, a ce que Ton 
considere le corpuscule germinatif comme etant equivalent a 
l’ensemble de la charpente chromatique des noyaux ordinaires 
[somatiques].” He concludes that there is no proof of the 
identity of the true nucleoli of the somatic cells with the ger¬ 
minal spots of egg cells. Two stages in the formation of the 
nucleolus may be distinguished in the ova of various Arachnids 
(Lycosa, Amaurobius , Argyronecta , Tegenaria , Attus, Theridium , 
Epeira , Zilla, Phalangium ): ( 1 ) there is a single large nucleolus 
(sometimes accompanied by smaller accessory ones), in which 
at first a few vacuoles arise, which later fuse to produce a single 
voluminous vacuole; and ( 2 ) the nucleolus becomes replaced 
by a mass of fine granules. In the ovarial egg of Amaurobius 
