No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 
309 
geneous, and a number of smaller globules, these latter stain¬ 
ing as the former, and some of them containing vacuoles: “ sie 
stellen einerseits eine Zusammenballung der bisher ganz unre- 
gelmassigen, im Keimblaschen vertheilten Chromatinsubstanz 
dar, ruhren andererseits aber wohl vom Keimfleck her.” These 
bodies have all disappeared in the ripe egg. 
Hubrecht (’87) noticed only a single nucleolus in the egg of 
Cerebratulus sp.; as to the egg of Pelagonemertes , he figures 
one nucleus containing one large and several smaller nucleoli, 
and another nucleus with only numerous small nucleoli. 
Kosinski (’87, ’93, mentioned by Lavdowsky, ’ 94 ): within the 
nucleolus of cancerous cells there is sometimes a vacuole, and 
within the latter a small body which Kosinski considers may 
correspond to Carnoy’s “ nucleoles-noyaux such nucleoli have 
the faculty of division, and of wandering through the nuclear 
membrane into the cytoplasm. 
Lukjanow (’87a), stomach epithelium of Amphibians: in the 
cytoplasm of the cylinder epithelium are structures of various 
form (“ Nebenkerne ”), which stain in general like the nucleoli. 
In some of the nuclei of the deep layer of gland cells each 
nucleolus is joined with a karyosome. 
Lukjanow (’87b) distinguishes three kinds of nucleoli in 
muscle cells of Vertebrates: ( 1 ) “ Plasmosomen ”; ( 2 ) “ Karyo- 
somen”; (3) “ Kernkorperchen von gemischtem Charakter.” 
The first stains deeply red (eosin), the second blue-violet (haema- 
toxylin), while the third stains a mixed color with these two 
stains (when used together). He remarks also: “ dass in 
manchen Kernen die Kernkorperchen ganzlich fehlen, in 
anderen entweder nur eine Kategorie derselben, oder mehrere 
zugleich vertreten sind. . . . Zuweilen liegt das Kernkorper¬ 
chen sogar ganz ausserhalb des Kernes.” 
Nussbaum (’87) found in smaller eggs of Hydra a single large 
nucleolus, while in larger ova several are present. “ In frischem 
Zustande sieht man in den allerersten Stadien neben den Keim- 
flecken noch eine blasse Kugel, die im Gegensatz zu den Nucle- 
olen des Keimblaschens keine Farbstoffe in sich aufnimmt.” 
O. Schultze (’87) studied the maturation of the egg in Rana 
and Triton. In the unripe germinal vesicle there are larger 
