No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 
345 
zum individuellen Zellleben, nicht zur Fortpflanzung; denn beim 
Beginn der Mitose verschwinden sie, um nach Beendigung der- 
selben — im Ruhestadium des Kerns — wieder aufzutreten.” 
He notes that their peripheral position is “ Eine Lage, die fur 
eine Wirkung auf den Zellleib die denkbar giinstige ist.” 
Brauer (’ 94 ), Actinosphaeriiim : in the cyst of the second order 
(“ Ruhecyste ”) there is a nuclear reticulum consisting of 
chromatin granules imbedded in a linin network, and usually 
numerous nucleoli of irregular form, arranged either in rows or 
circles. Probably the nucleoli take no part in the formation 
of the chromosomes, and are equivalent to those of metazoan 
cells ; they disappear in the prophase of mitosis. 
Bunting (’ 94 ) found in the eggs of Hydractinia and Podoco- 
ryne a single large nucleolus, containing one central vacuole of 
large size. 
Flemming’s (’ 94 ) “ Referat ” includes some of the more 
recent papers on nucleoli. 
Foot (’ 94 ), egg of Allolobophorci: during the first maturation 
division the nucleoli are distributed in the cytoplasm. Each 
pronucleus contains from one to seven nucleoli: “ the nucle¬ 
oli persist during the cleavage spindle, but how much later I 
am unable at present to state.” 
Hodge (’94), nerve cells of Rana stimulated by the electric 
current : amoeboid movements of the nucleolus were noticed; 
“ it was possible to make out granules in the nucleolus which 
moved slowly about and in several instances were seen to be 
extruded into the nucleus”; and in cells which had not been 
stimulated, but simply fixed in osmic acid and stained with 
safranin, “ the granules were stained brighter red than 
the body of the nucleolus, and several were, found partially 
extruded.” 
Lavdowsky (’ 94 ) studied nuclei from the epidermis of the 
fins of Amphibian larvae, as well as various tissues of plants. 
The nucleolus consists of : (i)an outer, thick “ Pyrenin-Chro- 
matinschale ”; (2) an enclosed vacuole ; and in the latter ( 3 ) 
the “Nucleololus ” (“das noch in Entwickelung begriffene 
Centrosoma”). The animal nucleolus varies from a spherical 
to an angular or star shape. In the resting nucleus the chro- 
