Igo9| GRIGGS—MITOSIS IN SYNCHYTRIUM 355 
Nevertheless, nuclei known to be derived by amitosis show four 
chromosomes. 
It is therefore concluded that in Synchytrium there is no morpho- 
logical or material continuity of the chromosomes from generation to 
generation of nuclei; but that the chromosome number is a physio- 
logical constant, like the other hereditary characters of the species. 
CoLtumMBus, OHIO 
Addendum 
After the foregoing paper had been completed and submitted for 
publication, Kusano’s “Contribution to the cytology of Synchytrium 
and its hosts’? (Bull. Col. Agr. Imp. Univ. Toyko 8: 80-147. pls. 
8-II. 1909) reached me. KUSANO’S paper, for the most part, is 
based on observations of S. puerariae, which seems to be remarkably 
similar to S. decipiens, which he also used for comparison. He gives 
much space to the metamorphosis of the nucleolus (karyosome), 
which is unusually favorable for study in Synchytrium, showing that 
all the elements derived from the mother nucleus are concentrated 
in the karyosome of the daughter nucleus from which they are later 
withdrawn. He-figures the prophases and metaphases of the primary 
mitosis, confirming for the most part STEVENS’ observations, but like 
him failing to find the anaphases and telophases, which for some 
reason seem to be very difficult to observe. He then devotes con- 
siderable space to the secondary mitoses, obtaining results similar 
'o those of the present paper; but his account of the prophases differs 
Considerably from that of the present writer. His series of figures, 
however, is not complete at this stage, and he admits (p. 102) that he 
had not been able to follow the formation of either the chromosomes 
or the spindle. Again, in the telophase there is a wide gap between 
his figs. 55 and 56, during which the aster is developed, a process 
about which he was left to conjecture (p. 127), incorrectly supposing 
that it originates from the cytoplasm. In addition to the method 
of segmentation by cleavage furrows described by HARPER, he reports 
4 second method in which the sporangium walls are precipitated by 
the cytoplasm as in the endosperm of the higher plants. This form 
of segmentation occurs also in S. decipiens and, according to my 
observation, is more common than that described by HARPER. 
