516 SAX: FERTILIZATION IN FRITILLARIA PUDICA 
are partly thread-like with large irregular pieces of chromatin 
scattered throughout. Fics. 35, 36 and 37 show the three nuclei 
completely fused. In Fic. 37, the outlines of the three nuclei 
can be seen but their common membranes have disappeared. A 
fine network is to be noted in the central part of the fused nuclei. 
Many cases of complete fusion were observed. ‘There is no 
question but that the two polar nuclei and the male nucleus com- 
pletely fuse and that no chromatin is thrown out in the process. 
The duration of the spireme must be very short, as only a few 
very clear spireme stages of the triple fusion, or endosperm 
nucleus, were found. A clear example of a late spireme stage is 
shown in Fic. 38. There is an irregular nucleolar mass to the 
left. At this stage the thread is thickened and apparently approxi- 
mately equally distributed throughout the nuclear cavity. The 
thread is just beginning to form chromosomes. The nuclear 
membrane has disappeared and delicate strands of cytoplasm 
are in contact with the forming chromosomes. 
The cases of first division of the endosperm nucleus were 
abundant and in every case appeared to be normal, apparently 
an equal number of chromosomes going to each pole. Fic. 39 
shows a very clear anaphase of the first division of the endosperm 
nucleus. The spindle is very clear in this and most other cases. 
The spindle is pointed at both ends. The first division of the 
endosperm nucleus results in the formation of two free nuclei- 
These divide rapidly and often the four or six nucleate endosperm 
is formed before the egg and male nuclei are completely fused. 
Aberrant fertilizations are occasionally-encountered. In three 
cases both the egg and the remaining synergid were being fer- 
tilized. The male nuclei were still distinct. In two of these 
cases the upper polar nucleus was in its usual position near the | 
egg apparatus, but unfertilized. In the third case the upper 
polar nucleus had almost reached the lower polar nucleus, having 
migrated alone. 
Two cases were observed where two pollen tubes had entered 
the ovule, one coming down the micropyle, the other entering the 
ovule at about the level of the egg apparatus. Only the pollen 
tube coming down the micropyle had entered the embryo sac. 
Besides the fertilization of the egg and polar nucleus there 
