473 
Sexual Nuclei in Lilium Mart agon. 
the spindle. The chromosomes behave daring karyokinesis 
as if their segments were drawn apart by the spindle-fibres to 
which they are attached h The spindles themselves when 
first formed are irregular in shape, sometimes triangular. My 
observations throw no light on their origin, and I have never 
been able to trace centrosomes at their poles. 
The curious formation of the lower antipodal nuclei by 
a process of direct or amitotic division is a pretty illustration 
of the general tendency among the nuclei of degenerating 
tissues to divide in that way. Mr. H. H. Dixon has found 
amitotic divisions in the endosperm of Fritillaria imperialist. 
The vegetative nucleus of the pollen grain goes a step further 
and does not divide at all. 
APPENDIX ON METHODS. 
A. Fixing. 
The ovaries, gathered between io A.M. and 2 P.M., were cut, 
and the cuticle was partly removed at once. They were then 
suspended in alcoholic Flemming’s solution for ij or 2 hours. 
The solution was made up as follows : — 
io 0 / chromic acid in water 
1 7 osmic acid . 
/ o 
Glacial acetic acid 
Absolute alcohol 
3 c - c - 
8 c.c. 
2 c.c. 
27 c.c. 
It will only keep for a few hours in the dark. The ovaries 
were then removed to •$°/ o aqueous solution of chromic acid 
for eighteen to twenty-four hours. This gives them a good 
1 In a communication to the Royal Microscopical Society (1895) I have 
expressed a different opinion concerning the first division of the pollen mother-cell 
nucleus. I do not now think that the contorted appearance of the chromosomes 
implies automatic movement on their part, but rather that it is due to the 
untwisting of the segments during separation. 
2 H. II. Dixon, Proc. Royal Irish Acad., 3rd ser., vol. iii. 
I i 2 
