DENDEOCOMETES PARADOXriR. 329 



impossible to count the number of chromosomes with any 

 degree of accuracy in this or in any other stage of division. 

 The mode of division of the chromosomes is also very 

 difficult to determine, but I have seen V-shaped appearances, 

 PL 18, fig. 13, very similar to those figured by Prowazek (22) 

 in Bursaria. I believe with him that these appearances 

 point to longitudinal division. 



The chromosomes separate into two parties, which travel to 

 the opposite poles of the spindle (fig. 5), where they apparently 

 fuse to form a solid irregular lump of chromatin. The 

 spindle then elongates enormously, so that the two chromatin 

 bodies are sometimes separated from each other by a 

 distance equal to three fourths of the full diameter of the 

 Dendrocometes. The spindle then becomes detached from 

 the chromatin and dissolves in the cytoplasm (fig. 6). The 

 stages in the division of the micronuclei are usually syn- 

 chronous in the two individuals, but sometimes one set of 

 figures is a little in advance of the other, as shown in fig. 5. 



By this division six micronuclei are formed in those 

 individuals which began the process with three. 



Stage D (tig. 7). — One of the five micronuclei of each 

 individual passes down the conjugative process to a position 

 very close to the membrane, where it enlarges and again 

 forms a mitotic figure. The other micronuclei degenerate 

 and disappear. 



The nuclei which are found close to the membrane give 

 rise by their division to the germ nuclei, to use the term 

 employed by Wilson (26). The division is always in a plane 

 parallel with the membrane (fig. 8) . 



Stage E (fig. 9). — The germ nuclei take up such a position 

 in contact with the membrane that each germ nucleus of an 

 individual is exactly opposite one of the other individual. 

 These nuclei consist of a clear vacuole containing a single 

 coarse skein of chromatin. The spindle entirely disappears. 



Stage F. — The germ nuclei then fuse in a manner shown 

 in PI. 17, fig. 10, and PI. 18, fig. 12, giving rise to the 

 cleavaafe nuclei of the two individuals. 



