No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 283 
germinal vesicles of various animals. In Eucope poly sty la there 
is one nucleolus in small eggs, several in riper ones: “ Es 
Hess sich hier feststellen, dass die zahlreichen Nucleoli durch 
Abldsung vom urspriinglichen einfachen Keimfleck entstehen.” 
Klein (’78) studied the stomach cells of the newt, and con¬ 
cludes “that in most cells the so-called nucleoli are local 
accumulations of the intranuclear network, that they are incon¬ 
stant in size and number, and that they are only transitory 
appearances.” 
Schindler (’78), Malpighian tubules of insects : after a cell 
has become obliterated by the outflow of its secretion, its 
nucleus becomes a new cell, and its nucleolus a new nucleus. 
Whitman (’78) found in the egg of Clepsine one to three 
nucleoli, each “ composed of several highly refractive pieces.” 
Bergh (’79) found in the egg of Gonothyraea (Campanularia ) 
a single large nucleolus, which is usually round, but sometimes 
with irregular outlines caused by slow amoeboid movements 
(observed in life), these motions being most vigorous later, 
when the nucleolus begins to divide. It increases in size, and 
acquires one or two vacuoles. In a later stage, but before the 
production of the pole bodies, there are a number of irregular 
nuclear bodies (staining as the original nucleolus), which had 
been produced by division of the nucleolus; in one case he 
actually observed the division of the nucleolus, which lasted 
half an hour, and at the same time the vacuole of the primitive 
nucleolus seemed to divide into two, so that each daughter- 
nucleolus received a daughter-vacuole. “ Oft macht es den 
Eindruck, als ob das Volum der secundaren Keimflecke zusam- 
mengenommen grosser ware, als das der primaren fur sich 
. . . eine active Wanderung der Nucleoli durch den Kernsaft, 
wie dies Auerbach [’74] bei gewissen Nematoden in den Vor- 
kernen gesehen hat, kommt wahrscheinlich hier nicht vor.” 
The nucleolus also divides in the egg of Clava. In the eggs 
of Psammechinus and Echinocardium , the single nucleolus 
begins to fragment before the chromatic network has disap¬ 
peared. The Phallnsia egg contains one large germinal 
spot, which probably disappears without fragmenting: “ich 
habe namlich unter Eiern, die im Keimblaschen einen scharf 
