1918 NOTHNAGEL—FERTILIZATION 149 
equatorial plate of the bipolar spindle; but even yet the third 
group of chromosomes is recognizable, as can be seen at the left in 
the group in fig. 25. 
After this stage the chromosomes contributed by each of the 
polar nuclei and by the sperm nucleus are no longer distinguishable 
(fig. 26). No trace of such distinction is seen in early metaphase 
or later spindle phases. How the various chromosomes finally 
arrange themselves upon the spindle and their distribution could 
not be ascertained in this investigation. When the 3x chromo- 
somes have gathered upon the equatorial plate of the bipolar 
spindle, each very much elongated chromosome splits longitudinally 
(fig. 26) preparatory to a typical equational division. No inter- 
mediate stages between early metaphase and early telophase were 
found. As the chromosomes reach the poles, they are somewhat 
shorter than when leaving the equator, and from the count, as 
seen in fig. 27, 3x chromosomes have passed to each pole. 
In the third division of the endosperm nuclei of Trillium 
grandiflorum a peculiarity was noted. In one of the dividing nuclei 
there were still to be seen the three groups of chromosomes upon the 
spindle, each group consisting approximately of six chromosomes, 
or the haploid number. It is easily seen that there is a great simi- 
larity in appearance between this third division of the endosperm 
and the first division of the primary endosperm nucleus. A similar 
stage was observed in the second division of the endosperm nucleus 
ot Lilium Martagon (fig. 29), showing in the upper dividing nucleus 
an appearance very similar to that seen in fig. 24. It was not 
determined how long endosperm division would continue in Lilium 
Martagon, as nothing older than 120 hours after pollination was 
collected. 
Fertilization of the egg and its first division 
Trillium grandiflorum furnished the best material for this phase 
of the investigation, as the later stages of the first division of the 
fertilized egg were not to be found in Lilium Martagon collected 
120 hours after pollination. 
In L. Martagon the chromatin of the egg and the sperm, at the 
time when the male nucleus lies coiled upon the egg, is similar in 
