TETRAD AND EMBRYO-SAC MITOSES 67 
Crucianella offered by far the more favorable material both on ac- 
count of the size of the cells and of the absence of unequal pressure 
due to peculiarities in the development such as occur in Asperula. 
The former has therefore received more exhaustive study, although 
in regard to certain points Asperula has given important results. 
When the ovule is young the embryo-sac-mother-cells are to 
be distinguished only by their greater size. During the early de- 
velopment of the integument, however, or even earlier, their cyto- 
plasm becomes denser. At about the same time a large number 
of fibers appear in the cytoplasm traversing the cells longitudinally 
but in somewhat irregular fashion. -The fibers are more or less 
curved and taper off at their ends. 
Inasmuch as the embryo-sac-mother-cells attain a strikingly 
great length before the first division takes place (pl. 10, fig. 16) 
and have their cytoplasm crowded with these fibers, they present 
a very unique appearance. In some cases the fibers traverse the 
cells from end to end, bending aside to avoid the nucleus. The 
condition here described apparently corresponds to that found by 
Mottier * and Dixon + in LZzuz, and by Duggar in Symplocarpus, 
during the earlier development of the embryo-sac mother-cell, ex- 
cepting in certain matters of detail and interpretation. 
From the figures of Mottier and Duggar one would judge 
that the fibrillar structures result from a rearrangement of the 
cytoplasmic reticulum. That the large thick fibers found by me 
in the developing embryo-sac-mother-cell are formed in the same 
way seems to me not to be the case, for, in addition to their great 
thickness, I have not been able to see a pulling out or distortion of 
the adjacent cytoplasm. Reference will be made to a possible in- 
terpretation of these structures beyond. 
Again, according to Mottier, the orientation of the fibers in 
Lilium is not constant in different cells of the same stage of growth. 
They may run in various directions or they may sometimes forma 
dense felt-like zone about the nucleus. Further, this cytoplasmic 
differentiation disappears before the commencement of mitosis, and 
+ Ueber das Verhalten der Kerne bei = an des Embryosackes und 
die Vorgänge bie der Befruchtung. Jahrb. 3 - 97. 
On the chromosomes of Lilium longi mm Proc. Irish Acad. 1 + 946, 
+ Studies in the en of the € grain in Symplocarpus ۳ and 
Peltandra undulata, Bot. Gaz. 29: 81. 
