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[Vol. XV. 
Bander auszumachen, sondern nur einen Bestandtheil derselben 
zu bilden, der bei mangelhafter Ernahrung der Gewebe zuerst 
schwindet.” 
Lang (’ 84 ) remarks of the egg cells of Poly clad Turbellaria: 
“Das Kernkorperchen oder der Keimfleck ist stets als ein 
kugliger, relativ sehr grosser, intensiv gefarbter Korper zu 
unterscheiden.” 
Vejdovsky (’84) noticed a single nucleolus in the eggs of 
Oligochaeta. 
Wielowiejski (’84) studied the egg cells of various Arthropoda . 
In the Araneina and Acarina the larger nucleolus contains a 
single large or several smaller vacuoles, though no pulsating 
or amoeboid movements were noticed (in opposition to the 
observations of Balbiani). In Drassus and Lycosa there is a 
small mass of granules in place of a germinal spot; in Oniscus , 
a single large nucleolus; in Astacus, numerous peripheral ones; 
and in Musca, a large, irregularly spherical one. (He notes 
that the germinal vesicle differs from all other nuclei in that 
its contents do not stain at all, or only faintly, with acetic acid 
methylen-green solution.) 
Will (’84) studied in life the eggs of Bufo and Rana. Larger 
and smaller nucleoli may be distinguished; the latter increase 
somewhat in size, but never attain the dimensions of the 
preceding. Those nucleoli, then, which lie close to the nuclear 
membrane cause small protuberances (“ Knospen ”) of this 
membrane, each such bud next breaks off from the nucleus, and, 
still enclosing a nucleolus within itself, wanders towards the 
periphery of the cell, and there becomes a “ Dotterkern,” the 
disintegration of which furnishes the yolk granules. 
1885. 
Van Bambeke (’85) reviews the opinions of the following 
writers in regard to the nature of nucleoli: Flemming (’82), 
Strasburger, Pfitzner (’81), Retzius (’81), Leydig (’83), Balbiani 
(’81), Korschelt (’84), R. Hertwig (’84), Van Beneden (’83), 
Frommann (’84), Carnoy (’84), Brass, Wielowiejski (’84), and 
Rabl (’84). Nucleoli are rarely absent, and hence they must 
be regarded as an essential element of the nucleus. “Le 
