No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 
349 
Schaudinn (’94) finds in Amoeba crystalligera a large nucle¬ 
olus, with “wabiger Struktur”; in the mitosis it divides into 
two equal parts. 
Watasd (’94), in the course of his theoretical deductions as to 
the structure of the cell, concludes in regard to the nucleolus: 
“ The nucleolus is not a permanent body in the nucleus. It 
may exist at one stage of the cell, and may disappear at the 
next. The micro-chemical reaction of the nucleolus is entirely 
different from that of the chromosome. It appears probable 
that three or more different bodies are included under the name 
of nucleolus. Indeed, one sees no reason why the inside of the 
nuclear membrane may not be used as a depository for some 
solid products of cell metabolism. . . . And thus some of the 
bodies included under the generic name of nucleolus may 
belong to the group of metaplasm.” 
H. V. Wilson (’94), Tedanione foetida: the youngest germinal 
vesicle contains a single, centrally placed nucleolus. Later 
there are two nucleoli, “ which are invariably placed on opposite 
sides of the nucleus and adhere to the inner surface of the 
nuclear membrane. In eggs which have reached the adult size 
it is the rule to find either one nucleolus peripherally placed, 
... or the nucleus contains no nucleolus at all. It sometimes 
happens that an egg of full size is found with two nucleoli, but 
this is rare. From this evidence it would seem that the two 
nucleoli present in the developing egg are lost, one after the 
other, at the time when the egg reaches its full size. As to 
how the first of the two is lost, I have no evidence, but the 
second nucleolus may often be seen lying just outside of the 
nucleus in the yolk, . . . showing that it has been extruded 
from the nucleus.” What Fiedler (’ 88 ) described as polar 
bodies in Spongilla are probably extruded nucleoli. In the egg 
of Hircinia acuia the nucleolar changes are as in Tedanione. 
1895 . 
Balbiani (’95), reviewed by v. Erlanger in Zool. Centralbl ., 
1895 , macronucleus of Spirochona : the nucleolus of the authors 
arises in a vacuole of the chromatin, and is formed by the 
separation of microsomes which fuse together to form one 
