88 G. CLIFFORD DOBELL. 
Or 
also known to occur in some filamentous Algz—in Sphero- 
zosma and Spondylosium (Desmidiacez),! and in Spiro- 
gyra, Zygnema, aud other Conjugate. A comparable 
process has also been described in the Metazoa—in the 
parthenogenetic egg of Artemia.? 
Now it appears to me, since observing the sporulation of 
B. spirogyra and B. lunula, that a much simpler interpre- 
tation of these phenomena in Bacteria is possible: namely, 
that we see here not a degenerate sexual process, but merely 
an abortive cell division. We have seen that a division takes 
place in B. spirogyra just before spore-formation, and that 
the daughter-cells which are so formed proceed to form 
spores without growing to their full size. We have only to 
suppose that this last cell division is not completed, to arrive 
at a result such as we see in B. biitschlii. There is, indeed, 
evidence to show that this last division may abort in B. 
spirogyra (ef. Pl. 13, fig. 18), so that individuals like the 
sporulating individuals of B. biitschlii result. My meaning 
will be made clearer by a glance at the accompanying figure 
(text-fig. B). 
I mean to say that the disporic individuals which we find 
in B. biitschlii and B. flexilis are really double indi- 
viduals—two individuals of the last generation of the lfe- 
cycle which have not been completely separated. It is a cell- 
division, not a sexual act, which has regressed. In Bac- 
terium lunula, I believe, the regression has not gone so 
far, so that the last cell-division may be complete—giving 
rise, therefore, to the monosporic individuals—or abortive,— 
giving rise to the disporic individuals, as in B. biitschlii. 
Schaudinn described abnormal monosporic individuals in 
B. biitschlii, and I also found them in B. flexilis. After 
I had reached the conclusions given above, I re-examined my 
old preparations of B. flexilis, and found several interesting 
abnormalities. In the first place, I found that the mono- 
1 De Bary, “Untersuchungen iiber die Familie der Conjugaten,” 
Leipzig, 1858. 
2 Brauer, ‘Arch. mik, Anat., 1893. 
