502 M. D. HILL. 
small size, however, I suggest that they were male pronuclei, 
though it is difficult to imagine what, if any, of the disinte- 
grated female pronucleus can eventually fuse with the male 
pronucleus.! 
SEGMENTATION. 
The division of the egg into blastomeres is, as I have said, 
vague and ill defined. I cut several ova into sections, but 
failed to see in any of them anything like a mitotic figure. 
All that could be seen were small resting nuclei with ill- 
defined archoplasms around them. I am, however, enabled, 
through Professor Hickson’s kindness, to reproduce two of 
his own figures (Figs. 6 and 7), showing that karyokinesis 
does take place, the archoplasms being very feebly developed 
though the centrosomes are well marked. 
SUMMARY AND CONCLUSION. 
Although the foregoing account is obviously incomplete, 
yet it is possible to draw some conclusions. I believe we 
have shown that: 
(a) The egg of Aleyonium produces no polar bodies in the 
ordinary sense of the word. 
(b) That the division of the female pronucleus before the 
entrance of the spermatozoon is irregular and amitotic. 
(c) That no chromatin leaves the egg in the stage of 
ovocyte I, to use Boveri’s nomenclature. 
(dq) That the female pronucleus completely disappears. 
(ec) ‘hat there are no bodies that can be termed chromo- 
somes throughout the whole process. 
(f) That the first segmentation nucleus is formed in a way 
(unknown) that must in any case be unlike anything hitherto 
described. 
1 It is interesting to note what Hargitt believes to be the fate of the sperm 
nucleus in Pennaria, whose course in the ovum he was unable to trace. “It 
seems,” he says, “to lose more or less completely its chromatophilous proper- 
ties soon after its entrance, nor does it appear to revive these characteristics 
in any appreciable degree, so far as I have been able to determine.” 
