296 Stras burger . — The Periodic Reduction of 
formed about the nucleus, each pole corresponding in position 
to a lobe of the cell. The four chromosomes now become 
differentiated in the nucleus of the spore-mother-cell, and 
undergo, as Farmer believes himself to be justified in asserting, 
double longitudinal splitting ; four chromosomes then wander 
into each developing spore : finally, the septa separating the 
four spores are completed. The same processes take place, 
according to Farmer, in the spore-mother-cells of Aneura. 
Photographs of the preparations, which I owe to the kindness 
of the author, bear out the correctness of his statements. 
It may appear superfluous to enter upon further speculations 
how the relations in the number of the chromosomes present 
themselves in the lower Cryptogams, the Fungi and Algae. 
I will, however, venture to formulate the problem which has 
to be solved with reference to these plants, in the hope of 
giving a stimulus to the necessary research. As a matter of 
fact, no countings of the chromosomes in the dividing nuclei 
in the lower Cryptogams have been undertaken : this is due 
partly to the great difficulty with which counting is attended, 
and partly to a lack of appreciation of the importance of 
these countings. The first question to be asked is, whether 
in these lower Cryptogams, in which a true alternation of 
diverse sexual and asexual generations does not take place, 
the number of the chromosomes in the nucleus is at all 
determinate ; and if it be so, whether and when a reduction 
takes place of the double number of chromosomes resulting 
from a sexual act. With regard, in the first place, to the 
question whether or not there is a determinate number of 
chromosomes in Algae and Fungi, I am inclined to answer it 
in the affirmative : for I was able to count twelve chromo- 
somes in the nuclear discs of Spirogyrct polyteniata 1 , which 
number was also determined by J. W. Moll in Spirogyra 
crassa 2 ; and I am almost certain of the uniformity in number 
of the chromosomes in Trichia fallax , an organism belonging 
1 Kern- nnd Zell-Theilung, p. 11 : Histol. Beitr. I, 1888. 
2 Observations on Karyokinesis in Spirogyra , Verh. d. Kon. Akad. van 
Wetensch. te Amsterdam, Tweede Sectie, Deel I, No. IX, 1893, p. 29. 
