5 1 2 MONTGOMERY. [Vol. XV. 



6. Amoeboid Movements, Divisions, and Fusions of Nucleoli. 



Amoeboid movements have been seen in life in metazoan 

 cells by the following observers (germinal vesicles) : A. Brandt 

 ('74, Blattd), Eimer ('75, Silurus), O. Hertwig ('76, Rana, 

 Pterotrached), La Valette St. George ('66, Libella; '83, Isopodd), 

 Bergh ('79, Gojtothryaed), Van Beneden ('69, '76, Polystommn, 

 Rand), Balbiani ('64, several genera of spiders), Leydig ('83, 

 Libella), A. Brandt ('78, numerous Insccta, Distonuwi), Van 

 Bambeke ('86, Blattd), Knappe ('86, Bnfo), Auerbach ('74a, 

 Teleostii). In somatic cells : Schwalbe ('76, sympathetic gan- 

 glion cells of Rand), Kidd ('75, epithelial cells from the mouth 

 of Rana), Hodge ('94, nerve cells of Rajia), Auerbach ('74b, 

 salivary gland cells of Musca). In Protozoa: Van Beneden 

 ('69, '76, Gregarina, Monocystis). In plants, Zacharias ('85) has 

 observed amoeboid movements in the nucleoli of CJiara (an 

 observation overlooked by Zimmermann, who states that such 

 movements have not been seen in plants). 



These observations would show that amoeboid movements 

 are probably natural phenomena of certain nucleoli, but one 

 should not be too positive of the naturalness of these phe- 

 nomena, since some of the observations were made upon the 

 heated stage, and in all of them the object was probably more 

 or less compressed and placed in artificial conditions. But they 

 are in all probability frequently normal phenomena, since, as we 

 shall see, divisions and fusions of nucleoli are certainly normal 

 and of wide occurrence, and the latter can only be classed as 

 forms of amoeboid motion. The question arises, Are these 

 movements wholly passive, caused by movements in the other 

 parts of the nucleus, or should they be considered an inherent 

 function of the nucleolus .-' The latter alternative would seem 

 the more probable, since no movements of the other nuclear 

 elements are known in the resting cell. Van Beneden ('69) has 

 described rhythmic expansion and contraction of the volume of 

 nucleoli in gregarines. But all these movements of nucleoli 

 should not be regarded as automatic motions of the nucleolus 

 in the sense that an Amoeba forms and retracts processes ; but 

 rather with Rhumbler ('93) they should be regarded as " Auf- 



