272 MOyTGOMERY. [Vol. XV. 



of the daughter-nuclei retained the original nucleolus, in the 

 other a new nucleolus soon appeared, first in the form of a 

 granular mass. 



In the paper by Balbiani ('64) movements of nucleoli are 

 described for the first time, and these observations were made 

 upon the living eggs. The first kinds of movements which he 

 distinguishes are exhibited by the eggs of spiders : " ces 

 mouvements de la tache germinative sont caracterises par la 

 production de prolongements transparents ayant presque tou- 

 jours la forme de lobes arrondis qui s'allongent et se retractent 

 alternativement." The second kind of movements is shown 

 in the egg of Phalangiiim, where there is a single large, 

 spherical nucleolus, which appears spongy, owing to the pres- 

 ence of a number of vacuoles, some of which " s'dlevent plus 

 ou moins au dessus de la surface en soulevant sous forme 

 d'une ampoule la couche la plus externe de la substance du 

 corpuscule. . . . Lorsqu'un porte son attention sur une de ces 

 vesicules superficielles, on ne tarde generalement pas ^ la voir 

 grossir insensiblement, en meme temps que la couche de sub- 

 stance qui forme sa parol exterieure se soul^ve en s'amincis- 

 sant de plus et plus ; puis, assez brusquement, cette parol se 

 rompt comme sous la pression d'un liquide interieur, et ses 

 bords se rdtractent vers la base adherente de I'ampoule qui se 

 trouve ainsi transform^e en une petite cupule ou excavation 

 superficielle, . . . et bientot il ne reste plus aucune trace de 

 I'ampoule ni de I'excavation qui lui a succ^d^." All the periph- 

 eral vacuoles discharge themselves thus in succession, while 

 at the same time the smaller central vacuoles increase in size 

 and wander towards the periphery to take the place of the 

 preceding. Balbiani compares these movements to those of 

 the contractile vacuoles of the Rhizopoda, but notes this dif- 

 ference : in the latter forms the vacuole always forms itself 

 at the same place again. In the eggs of Gcophihis and of 

 Helix pomatia he finds that the vacuole discharges through a 

 small orifice. 



Balbiani ('65b) describes some remarkable structures in ger- 

 minal vesicles, all studied in life. In Geophilus longicornis 

 there is an external infundibular canal extending from the sur- 



