1918] NOTHNAGEL—FERTILIZATION 157 
of chromosomes is pulled in upon it. In each group there are 
approximately six, the haploid number. 
In 1891 GUIGNARD (6) pointed out in Lilium Martagon that 
there were two spirems and that one-half of the chromosomes on 
the spindle were contributed by the male parent and one-half by the 
female parent. No drawings were made to substantiate these 
views, and Ernst (3) and Mortrer (13) apparently made it so 
conclusive that there was a complete fusion or intermingling of 
chromatin that GuIGNARD’s earlier views were discarded and prac- 
tically forgotten. In later papers GuIGNARD himself did not place 
much emphasis upon these earlier views. 
SAx (16) stated that a spirem was frequently found in the egg 
and sperm before fusion occurred (fig. 21), but says “the rare 
appearance of such cases as that of the spirem stage in the egg 
and male nuclei when their outlines are still distinct, is probably 
of little significance in this respect. It is probable that these nuclei 
subsequently fuse completely, because no later stage of incomplete 
fusion was found.”’ 
Many writers have looked upon the number of nucleoli present 
in the fertilized egg as an indication that fertilization has or has not 
occurred. This, as Ernst (3) has pointed out, is not a safe indi- 
cator, for, as shown in figs. 5, 6, 9, 19-23, the nuclei have already 
united and from two to many nucleoli are present. 
SAX (16) says “fig. 19 shows a stage where the common boundary 
has disappeared, the contents apparently mingled, and those from 
the male and female nuclei are not to be distinguished.” In case 
of the formation of the fertilized egg, as in the formation of the 
primary endosperm nucleus, the writer is unable to agree with Sax 
and the earlier writers that there is a complete fusion or inter- 
mingling of the chromatin of the egg and the sperm; the material so 
plainly shows that the two remain separate from the time of coming 
together until the formation of the daughter nuclei. What happens 
after that does not come within the scope of this paper. 
Conclusions 
From the stages that have been found in the fertilized egg leading 
up to the first division, and in the primary endosperm nucleus up to 
