33O WOOLFORD B. BAKER. 



As they separate the bodies again divide giving rise to the 

 blepharoplasts of the two future cells. From each blepharoplast 

 a new flagellum arises. When the nucleus has passed anteriorly 

 until it comes into contact with the lower border of the reservoir, 

 each blepharoplast divides, giving rises to a basal granule which 

 serves as the basis for the smaller branch of the bifurcated 

 flagellum (Fig. 6). In some cases the mass from the endosome 

 does not follow this sequence, but both roots of the flagellum 

 begin to grow out directly, the blepharoplast and basal granule 

 forming later. This is much as described by Hartman and 

 Chagas for Spongomonas. 



(b) Formation of Chromosomes. The chromatin which in the 

 resting nucleus is observed at the nodes of a linin network in the 

 form of granules and masses of various sizes, now collects in a 

 number of separate rods or filaments, the chromosomes (Figs. 3, 

 5). The entire nucleus stains more heavily at this time than in 

 the vegetative stages, and gives the appearance of containing 

 more chromatin. It is perhaps true that the chromatin masses 

 increase in bulk and underg^phemical transformation so as to 

 give the changed appearance. The dumb-bell shape observed in 

 the resting nucleus may still be observed, as the chromosomes 

 become outlined. Each is seen more or less constricted at first, 

 later becoming almost uniform in width. All the chromosomes 

 do not form simultaneously, hence the areas where the separate 

 chromatin masses are beginning to fuse to form the chromosomes 

 show what might be interpreted as a spireme structure. Free 

 ends may be distinguished however, so that one is led to believe 

 that a continuous spireme is not formed but rather each chromo- 

 some retains a certain degree of continuity or individuality which 

 has persisted throughout the resting stages, the chromosome as 

 such reforming in the prophase from the chromatin network. 



As the filaments or rods assume definite outlines they are seen 

 to be more or less looped. This appearance is perhaps due to the 

 fact that the chromatin has increased in bulk while the nuclear 

 membrane has persisted and has not enlarged in proportion. .The 

 looped shape might easily be mistaken for a paired arrangement 

 of separate units, especially as the chromosomes come to lie in the 

 equatorial region and the ends of the loops become pressed close 

 together (Fig. 7). 



