No. 2.] COMPARATIVE CYTOLOGICAL STUDIES. 315 
Scharff (’ 88 ) studied the maturation of the eggs of various 
Teleosts. In the smallest ova examined (.011 mm.) there are 
numerous peripheral nucleoli, and a few which are central in 
position. In larger eggs (.03 mm.) “ the nucleoli show an 
inclination to gather still more towards the periphery of the 
nucleus . . . one or more of the nucleoli become larger than 
the others, and in their interior refractive specks are visible 
which have sometimes been described as endonucleoli.” In 
still larger ova (.08 mm.) “in some cases the big nucleoli dis¬ 
appear almost completely, leaving an unstained part around 
them.” In Conger he “noticed a small nucleolus being con¬ 
stricted off from a larger one.” He figures outside of the 
germinal vesicle of Gadus certain granules, and these he 
considers are emigrated nucleoli which are destined to become 
dissolved there, though he holds it possible that “some find 
their way to the surface of the egg to form the nuclei of the 
follicular epithelium” ; in eggs which have attained the 
dimensions of .132 mm. the nucleoli become very irregular 
in shape. In the Trigla egg of .13 mm. the surface of the 
nucleolus is raised into small protuberances, most of which 
contain a nucleolus ; these protuberances later break off and 
become the yolk spherules (in corroboration of Will, ’84). 
Schewiakoff (’ 88 ), Euglypha: the nucleolus gradually dis¬ 
appears in the prophasis of mitosis. 
Steinhaus (’ 88 ), intestinal cells of Salamandra; karyosomes 
and plasmosomes are distinguished within the nucleoli, and are 
usually combined in pairs with one another. Plurinucleolar 
nucleoli are formed by continued divisions of a single nucleolus, 
“et les nouveaux nucldoles s’dloignent Tun de l’autre, probable- 
ment a l’aide de mouvements amoeboides ou d’autres qui leur 
sont propres.” Plasmosomes when extruded into the cytoplasm 
increase greatly in size, though this increase is due to mere 
imbibition of some substance ; each such extruded nucleolus, 
combining with a karyosome, develops into a new nucleus. 
Vejdovsky (’ 88 ) studied the maturation of the egg of Rhyn- 
chelmis. The embryonal genital cells contain no true nucleoli. 
The nucleolus does not stain when it first appears (in very 
young stages). Subsequently it is always excentric in position, 
