On the Prophases of the Heterotypic Mitosis in the 
Embryo-sac Mother-cell of Lilium. 
BY 
DAVID M. MOTTIER, 
Professor of Botany in Indiana University . 
With Plate XXIII. 
I N a recent paper, dealing with the development of the heterotypic 
chromosomes in the pollen mother-cells of Lilium and in certain 
other plants, attention was directed to the fact that the chromatin in the 
stage just preceding the synaptic contraction appeared as larger and 
coarser lumps in some cells of the same loculus than in others. On the 
one hand the chromatin was found to be distributed upon the linin reticulum 
in the form of relatively large lumps (Mottier, ’ 07 , Figs. 17, 22), in which 
condition the nucleus passed into synapsis ; and on the other hand, a readily 
Hstinguishable and distinct thread with small and uniform chromatin 
o anules represented the contracting mass ( 1 . c., Figs. 19, 20, 21). It was 
suggested as a probable explanation that the action of the fixing fluid 
might have been in a measure responsible for this behaviour of the 
chromatin, and it was with the view of determining more definitely the 
effect of the reagents, as well as ascertaining more fully the early develop- 
ment of the heterotypic spirem in the megaspore mother-cell of Lilium 
as compared with that in the pollen mother-cell, that I undertook this 
investigation. With these two objects chiefly in view, a careful study 
of the prophases of the heterotypic mitosis was made in the develop- 
ing megaspore mother-cell of Lilium , L. Martagon , and L. candidum 
being used. 
Methods. 
The same methods of fixing and staining were used as in the study 
referred to in the preceding. However, before the ovaries were placed 
in the killing fluid (chrom-osmic acetic acid of the writer’s formula), the 
walls of the ovaries were carefully cut away with the razor on the sides 
opposite the loculi, so that in some cases only a very thin layer of tissue 
was left to enclose the cavity ; in others the wall was cut away, laying 
[Annals of Botany, Vol. XXIII. No. XCI. July, 1909.] 
B b 
