Notes. 
3i9 
spring, at the suggestion of Professor Farmer, an examination of 
the embryo sac of Caltha palustris. 
The material I obtained from Hackbridge, and pickled on the 
spot in Flemming’s fixative. 
After cutting a great many ovaries, which yielded almost all stages 
before and after fertilization, I at last hit upon the exact fertilization 
stage, and in an embryo-sac, which shows most perfectly the some¬ 
what attenuated S-shaped male nucleus just touching the ovum, is an 
excellent instance of a much coiled vermiform nucleus wrapped round 
the polar nucleus. The pollen-tube is also present. In a neighbour¬ 
ing embryo-sac, the male nucleus is actually fusing with the ovum, 
while there is a most suggestive polar fusion. Normally the polar 
nuclei unite before fertilization, and although one might readily suppose 
that this process could be delayed, it is impossible to imagine that this 
alone could give the appearance seen. For in addition to an irregular 
nuclear mass—the polar nuclei—is another nucleus of different char¬ 
acter, and without a nucleolus, closely adpressed to it. All the other 
nuclei of the sac are present. 
These, and many other similar cases of polar fusion, were sufficient 
to convince me that a fertilization of the polar nuclei by a vermiform 
nucleus actually took place in Caltha as in Z. Martagon; but as 
fusion had begun in most instances it was often impossible to follow 
the outline of the vermiform nucleus in its entirety. 
However, in another ovule of the same ovary that gave the embryo 
sacs just described, and only a few sections off in the microtome 
series, is another perfect instance of a vermiform nucleus, the sharp 
coils of which can be followed quite distinctly. 
I have this spring very carefully pickled a quantity of new 
material, for the purpose of obtaining a more complete series of 
sections showing, if possible, the fusion in all stages; and of deter¬ 
mining if any points of difference exist in this matter between Caltha 
and Lilium Martagon . 
The work has been done hitherto at the Royal College of Science, 
South Kensington, and I wish to thank Professor Farmer for his 
great kindness and assistance, and also Miss Sargant for her in¬ 
valuable advice. 
ETHEL N. THOMAS, Reigate. 
