342 SYDNEY J. HICKSON. 



continuous. The statement of tin's fact was made in my 

 preliminary communication (Hickson^ 1900, 12). I am not 

 the first, however, to maintain that the meganuclei of the 

 Infusoria fuse. In 1867 Stein made the following statement 

 concerning the Acinetaria (Stein, ' Der Organismus,^ vol. ii, 

 p. 139), 1867 : 



" Die conjugation verlauft anch bei denjenigen Acineten, 

 bei welchen sie bisher genauer studirt wurde, im Wesent- 

 lichen auf dieselbe Weise, wie bei der gleichartigen 

 Conjugation der Yorticellen ; es verschmelzen zuerst die 

 Korper der beiden Acineten zu einem einzigen, nnd dann 

 fliessen audi deren Nuclei in einem gemeinsamen Nucleus 

 zusammen." 



Biitschli (2) gives a figure (pi. Ixxiii, 96) of two attached 

 Vorticellids in which the meganuclei are in junction, but 

 considers that this is doubtfully a case of conjugation. 

 Schneider (24), in Stylocometes, figures the junction of the 

 meganuclei in two individuals that are conjugating, but 

 suggests that this also may be a case of fission. Biitschli 

 may have been right as regards his VorticelHds, but such a 

 method of fission as Schneider suggests for Stylocometes is 

 extremely improbable. In a recent paper by Prowazek (22) 

 a number of new and excellent figures are given of the 

 nuclear phenomena during the conjugation of Bursaria, and 

 it seems probable from these that in this ciliate Infusorian 

 there is a junction of the meganuclei before they disintegrate. 

 Unfortunately Prowazek's description is not very clear, and 

 he does not attach much importance to the phenomenon. 



In my preparations of Deudrocometes I have at least three 

 cases in which the meganuclei actually touch, but a consider- 

 able number in which they approach one another very closely 

 in the conjugative processes. That the junction is not 

 merely casual contact, but actual organic connection, is 

 proved by the preparation Avhich is repi'esented in PI. 18, 

 fig. 11. Here there is no sign of any boundary between the 

 two nuclei, and the chromatin grannies are fixed in such a 

 manner as to suggest very forcibly that during life they were 



