278 The Ohio Naturalist. [Vol. VIII, No. 5, 



mav favor, with the hope of correlating the cytology of Synchy t- 

 rium with that of other plants and animals, in a way which may 

 throw some light on some general problems of cell organization 

 and finally to arrive at some conclusions regarding the relation- 

 ships of the Chytridiales. 



Observations.* 



After the division of the primary nucleus of Synchytrium decip- 

 iens which species alone was used in the present investigation, 

 the secondary nuclei divide rapidly without the formation of cell 

 walls till segmentation takes place when there are usually 500- 

 800 nuclei in the cyst. Kusano reports that all these mitoses 

 are similar in 5. puerariae and such seems to be the case in 5. 

 decipiens, the only change being in the continual diminution in 

 the size of the nucleus. But while it is believed that all of the 

 mitoses are similar it must be remarked that all of the observa- 

 tions here presented, were made on cysts about midway between 

 the primary cell and the segmented sorus in respect to the num- 

 ber of nuclei, i. e., from cysts wnth 100-300 nuclei. Whether 

 this has any significance or not we do not at present know. 



The spindles of Synchytrium like those of fungi generalh-, 

 arise within the nucleus and reach metaphase before the nuclear 

 membrane is dissolved from around them. As Stevens found 

 both in the primary mitosis and in the succeeding ones, no cen- 

 trosomes are demonstrable at the poles. The figure made by the 

 separated chromosomes at each pole in anaphase (fig. 1 ) resem- 

 bles greatly that of the same stage in the primary division, com- 

 pare Stevens's (03) fig. 13 with my fig. 1, thus strengthening the 

 statement that all the mitoses are similar. There appear to be 

 four chromosomes as Stevens supposed though it is sometimes 

 difficult to see more than three (cf. figs. 1, 2, 8. In figure 1 there 

 are four chromosomes at the pole where only three can be seen, 

 one being directly beneath the one shown nearest the nucleolus.) 



By the beginning of the telophase the daughter nuclei are 

 separated by an unusually great distance from each other. In 

 the mitoses from which the present figures were drawn they are 

 about 20 microns apart (see figs. 1 and 12.) Such a condition as 

 is shown in figure 5 where the daughter nuclei lie close together is 

 quite unusual. It is readily seen that in thin sections the 



* Since the observations herein recorded were made but before they 

 were embodied in their jjresent form Kusano (07) has pubHshed a prelim- 

 inary paper on Synchytrium puerariae in which he announces the same rela- 

 tion'of the centrosomes to the nuclear membrane as is herein described. 

 Though he gives five figures they are hardly sufficient to demonstrate his 

 point and his fuller ])a])er is to be much desired inasmuch as the action of 

 the centrosomes of Synchytrium are so unusual that confirmation of the 

 results by independent workers will undoubtedly be welcomed by the 

 cytological fraternity. 



