
19 13] YORK—DENDROPHTHORA 10g 
have become concentrated into a single nucleolus-like body, which 
stains uniformly and reacts with Flemming’s triple stain, Haiden- 
hain’s iron alum hematoxylin, cyanin and erythrosin, thionin, and 
methyl green and acid fuchsin, as chromosomes do in ordinary 
mitotic cell division. The division of the nuclei apparently always 
begins by a fission of this nucleolar mass, which is followed by a 
constriction of the nucleus (figs. 39, 40). This mass divides into 
a number of parts equal to the number of nuclei to be formed. 
For example, in the division of the parent nucleus of the egg 
apparatus, the nucleolus divides into 3 or 4 parts, each of which 
later becomes inclosed within a nucleus (figs. 36, 38). The staining 
reaction and the mode of division of the nucleolus-like body of 
the nucleus as thus seen clearly indicates that it is composed 
of chromatin, and instead of dividing into the same number of 
chromosomes as occur at the time of the division of the megaspore 
mother cell, it divides only into 3 or 4 parts. Judging from all 
appearances, the nuclei during the above mentioned period divide 
amitotically. The manner of the formation of the gametophytic 
nuclei is apparently quite unique, as the author has found thus far 
no indication in the literature that such a phenomenon has hitherto 
been observed in the development of an embryo sac. The mode 
of division of these sac nuclei is probably stimulated in some way 
by the presence of abundant food material within the sac. 
A number of examples were found where 1-3 small bodies, 
which stained like the chromatic material in the nuclei of the same 
embryo sacs in which they occurred or as described in connection 
with figs. 39, 40, were present in the terminal portion of the embryo 
sac in the dense finely granular protoplasm mentioned above 
(figs. 32, 33, y). It was not possible to discover their origin or fate. 
Brown UNIVERSITY 
PROVIDENCE, RHopE IsLAND 
EXPLANATION OF PLATES V AND VI 
All figures, with the exception of figs. 8, 12a, 20, and 21, which are diagrams, 
are camera lucida drawings from microtome sections. Figs. 3, 6, 22, and 66 
were made with a Bausch and Lomb dissecting microscope. In making the 
remainder of the drawings a Leitz compound microscope was used 
Abbreviations: a, floral apex; an, antipodals; 6, bracts; c, swollen collar 
