62 
therefore, that every egg when laid consists of two oöcytes which 
have united end to end, the posterior or older odcyte being provided 
with keimbahn-chromatin derived from the chromatin of its nucleus, 
and the anterior supplied with a nucleus which has arisen from the 
disintegration of a spindle similar to that from which the keimbahn- 
chromatin originated. 
Discussion. 
The principal phenomena observed in the preceding study that 
require discussion are: (1) the nature of the processes which result 
in the formation of the keimbahn-chromatin, and (2) the origin of 
the nucleus of the egg, involving a fusion of oöcytes in pairs end 
to end. 
The first question to be considered is whether the spindle which 
appears in the young oöcytes is comparable to the first maturation 
spindle in the eggs of other animals, or is a special structure destined 
to produce the keimbahn-chromatin. The first maturation spindle in 
animal eggs may be formed either before or after fertilization, and 
either before or after eggs are laid depending upon the species and 
to a certain extent upon the environment. SıILvEsTrI has shown that in 
both the parthenogenetic and fertilized eggs of monembryonie and poly- 
embryonic parasitic Hymenoptera the polar bodies are all formed after 
the eggs are laid. Nevertheless, the spindle in the young oöcyte may 
be a precocious maturation spindle which never fulfills its original 
destiny. ‘The spindle is peculiar not only because of its large size 
and the absence of asters. It was pointed out in the descriptive part 
above that the chromatin in the nucleus of the odcyte appears to 
form a spireme which segments into rod-shaped chromosomes; these 
chromosomes seem to unite at or near their ends and then become 
drawn out upon the spindle which has formed in the meantime. 
More material will be required before a definite statement can be 
made regarding the history of the chromosomes on the spindle, but 
the evidence thus far obtained points strongly toward a series of 
processes like that just enumerated. 
A number of references are present in literature to what have 
been termed ‘uterine’, ‘disappearing’ or ‘aborting’ spindles. Such 
a spindle was first noted by SerenkA (81) in the turbellarian Thy- 
sanozoön diesingii. Here apparently a completely developed maturation 
spindle was observed in the fully grown eggs after.they had entered 
