No. 2 .] COMPARATIVE CYTOLOGICAL STUDIES. 
I have found a wandering of nucleolar substance out of rest¬ 
ing nuclei in one very beautiful and unique case, namely, in the 
subcuticular gland cells of Piscicola; at one stage in its cycle 
of development the nucleus commences to contract in volume, 
and in so doing discharges all except a single one of its nucleoli 
into the cytoplasm. This and certain of the observations cited 
from other investigators show that a discharge of nucleolar 
substance from the resting nucleus takes place in some cells. 
But the more recent observations of Morgan, Floderus, and 
others on Tunicate development render it very probable that 
Fol and Roule were mistaken in assuming that the nucleoli 
which pass out of the germinal vesicle become the constituents 
of follicle cells. There is still some question, also, as to whether 
the nucleolar substance in the cytoplasm takes any part in the 
formation of the yolk substance. Other pertinent observations : 
Mertens (’93), Bremer (’95a, b), Kosinski (’87, ’93), Galeotti (’95), 
Melissinos and Nicolaides (’90), Auerbach (’74), Ver Ecke 
(’93), Steinhaus (’88), Rohde (’96). 
11 . Behavior of Nucleoli during Nuclear Division. 
It is in cases of nuclear division that the nucleolus has 
received the most attention from morphologists. The behav¬ 
ior of the nucleolus in mitosis and amitosis may be treated 
separately. 
i. Amitosis. — In this mode of nuclear division it is frequently 
the case for the nucleolus to divide first, so that each of the 
daughter-nuclei receives a half, or approximately a half (for the 
division of the nucleolus is not always into two equal parts), 
of the parent-nucleolus. In support of this deduction the fol¬ 
lowing observations may be mentioned : Schaudinn (’94, Amoeba 
crystalligera)\ F. E. Shulze (’75, A. polypodia)\ Will (’85, ova of 
Nepa , Notonecta) ; Doflein (’96, degenerating ova of Tubularia) ; 
Carnoy ('85, ova of Gryllotalpa y Lithobius , Geotrupes ); Korschelt 
(’95, intestinal cells of Ophryotrocha ); my observations on the 
peritoneal cells of Polydora; Hoyer (’90, intestinal epithe¬ 
lium of Rhabdoncma ); Frenzel (’93b, hepatopancreas cells of 
Astacus ); Platner (’89a, Malpighian tubes of Dytiscus ; Wheeler 
