DENDROCOMETES PARADOXUS. 343 



flowing from one side into the otlier. Apart from this 

 evidence, however, attention may be called to the fact, Avhich 

 is evident not only from my own preparations (PI. 18, figs. 

 6 — 8), but also from Schneider's figure of Stylocometes, that 

 when the points of the meganuclei pass down the conjugative 

 processes they converge to the same spot on the membrane. 

 This shows, I think, that there is some force at work which 

 is bringing them together. Sand refers to this in Stylo- 

 cometes when he says, '^Les deux noyaux s'approchent et se 

 placent dans le bras dilate vis-a-vis I'un de I'autre separespar 

 une couche de plasma." But he adds, '' Pourquoi, dira-t-on, 

 les noyaux vont-ils se placer dans le pont qui reunit les deux 

 Stylocometes ou les deux Dendrocometes? C'est peut-etre 

 pour diriger les echanges et les mouvements qui ont lieu dans 

 ce pont." 



The organic junction of the two meganuclei lasts a very 

 little while, I believe, and it is probably followed immediately 

 by their disintegration. Each meganucleus breaks up into a 

 number of irregular lumps, in each of which there are at first 

 several granules of unaltered chromatin. A large piece of 

 darkly staining substance is frequently present in these 

 lumps, but in jnany of them the central parts are simpl}^ 

 vacuolated (PI. 18, figs. 15 and 19). 



In the next stage the cytoplasm is filled with numberless 

 vacuoles, granules, and lumps (PI. 18, fig. 19) of endless forms, 

 sizes, and colourable property. In such a pi-eparation as that 

 from which the figure was drawn, it is almost impossible to 

 distinguish the various remnants of the old meganuclei from 

 food bodies and micronuclei. 



The mode of formation of the new meganucleus at the 

 close of conjugation is of great importance and interest. 



I must confess that in the earlier stages of this investig-a- 

 tion I had some hesitation in believing that the new 

 meganucleus is formed from a product of the segmentation 

 nucleus. The descriptions, and more particularly the figures, 

 of the nuclei of conjugation in Ciliata by Maupas (20), 

 Hertwig (8), Hoyer (14), and others, although unanimous 



