514 MONTGOMERY. [Vol. XV. 



a somewhat similar method of formation of the smaller nucleoli 

 of Gregarina blattarwn. Now I found in the nucleus of the 

 gregarine from Liiieus numerous nucleoli of different dimen- 

 sions, and often irregular in their outlines ; and this irregularity 

 in form would point not only to amoeboid movements of the 

 nucleoli, but also to nucleolar divisions, since in the largest 

 nuclei we find a large number of small nucleoli. All appear- 

 ances showed that these smaller nucleoli are division products 

 of the larger ones ; but it seems that they simply bud off from 

 the surface of the latter, and are not preformed in their interior. 

 In other words, Schneider and Marshall are probably correct 

 in concluding that the smaller nucleoli are disassociated portions 

 of the larger ones ; but they may perhaps be mistaken in 

 assuming that they are preformed in the interior of the latter, 

 since these investigators may have mistaken vacuoles for intra- 

 nucleolar nucleoli. (Other observations on nucleolar divisions 

 in resting cells : Hermann, '89 ; Vejdovsky, '95a ; Biitschli, '80 ; 

 R. Hertwig, '76 ; Kultschitzky, '88 ; Bergh, '79 ; Bannwarth, '92 ; 

 Stuhlmann, '86 ; A. Brandt, '78 ; Scharff, '88 ; Eisig, '87 ; 

 Cunningham, '95 ; Kosinski, '87, '93 ; Carnoy and Lebrun, '97a ; 

 Steinhaus, '88 ; Cuenot, '91 ; Metzner, '94.) 



Fusions of nucleoli are not as widely known as divisions, but 

 there are some facts which would show that the former processes 

 are by no means unusual in their occurrence. Such fusions 

 have been described for cells of plants by Zacharias ('85), Mann 

 ('92), and Wager ('93) ; for animal cells by Rhumbler ('93, '95), 

 Brauer ('9l), Leydig ('50), Pfitzner ('83), and Riickert ('92). I 

 have found fusions of the nucleoli to be characteristic phenomena 

 of certain stages in the maturation of the germinal vesicles of 

 nemerteans, an extreme case being furnished by Stichostemvia, 

 where sometimes all the nucleoli may fuse together at the 

 center of the nucleus, and so produce a single large one. The 

 nucleolus at the time of its origin may be said to be undergoing 

 a process of fusion, since it is produced by the coalescence of 

 numerous smaller portions of nucleolar substance. There is 

 nothing problematical in regard to the fusion of nucleoli, since 

 it is a physical property for bodies of like nature (when fluid) 

 to fuse together when they come into contact, though this 



