356 MONTGOMERY. [Vol. XV. 



Substanz ist. Das oben eingehend besprochene Verhalten der 

 Embryonalkerne Hess dagegen eine ganz andere Auffassung zu, 

 obwohl es auch bei diesen allerdings abnormer Weise vorkommt, 

 dass neben den bereits gebildeten Chromosomen (sogar in der 

 angelegten Spindel) der Kernkorper noch vorhanden ist. . . . 

 Was die erwahnten Verschiedenheiten des Verhaltens der 

 Nucleolen in dam Ei- und Embryonalzellen betrifft, so liessen 

 sich diese vielleicht durch die recht verschiedenartige Ausbil- 

 dung und Funktion der Kerne in den beiderlei Zellen erklaren." 



Lauterborn ('95a), nuclear division of Ceratium, hirundinella : 

 from one to four oval nucleoli are present and are frequently 

 apposed to the nuclear membrane. One nucleolus is still 

 present in the spirem stage (the mitosis advances no further 

 than this); but he was unable to decide whether this nucleolus 

 divides into two. 



Lauterborn ('95b), Midticilia : each nucleus contains a rela- 

 tively large nucleolus, which frequently shows a " netzig- 

 wabige" structure. 



Macallum ('95) concludes that less iron is contained in the 

 nucleolus than in the chromatin, as is shown by its lighter stain 

 with haematoxylin. Nucleoli "are always attached to the 

 chromatin network, and sometimes there appears about them a 

 membrane derived from, and continuous with, the fibrils with 

 which they are connected." In a nucleus of a gland cell from 

 the kidney or liver of Ncctiirus "which is passing into the 

 mitotic phase, the nucleolar body disappears, apparently by 

 solution into the chromatin threads, for in the nucleus of a renal 

 cell, in which the meridional disposition of the chromatin 

 filaments obtained preparatory to the formation of the loops, I 

 saw, attached to one of the filaments and partly embraced by 

 its substance, what appeared to be the remains of such a body." 

 The nucleoli of the amphibian ovum are derived from the 

 chromatin of the nuclear reticulum. In support of his previous 

 observations ('91) he adds, "that the iron in the cytoplasm of 

 the ovum makes its appearance only after the solution of the 

 peripheral nucleoli commences." In plant cells (Erythroniuvi) 

 there are at least three kinds of nucleoli : the first stain 

 intensely with eosin ; the second are composed of chromatin ; 



