1 1 6 Walker . — On Abnormal Cell-fusion in the 
present paper. In a recent contribution upon spermatogenesis in the 
Bryophyta by Malcolm Wilson ( 22 ) an adequate historical outline of the 
subject was given, and this will not be repeated here. Reference to recent 
work will be made in the descriptive part of the paper. 
Methods. 
The material was fixed in the field during June, when all stages in the 
development of the antheridia are present as well as both young and 
old archegonia. The air was removed from the tissues by means of an air- 
pump. Zenker’s mixture, acetic alcohol, and various strengths of Flem- 
ming’s solution were tried as fixing reagents, but the best results were 
obtained by the use of Flemming’s strong solution diluted with an equal 
volume of water. The objects were dehydrated by the glycerine method 
and brought gradually into cedar oil, through several mixtures of this 
oil and absolute alcohol. The introduction to paraffin was also gradual by 
means of successive baths in mixtures of the cedar oil and wax. The 
material cleared in this way was found to be less brittle than when 
chloroform was used. The stay in paraffin was made as short as possible ; 
five or six hours usually sufficed. Sections were made of 3 fx ~6 [x in thick- 
ness. In staining, the best results were obtained by Heidenhain’s iron- 
haematoxylin method preceded by a 12-24 hours’ treatment with a solution 
of Bordeaux R. Flemming’s triple stain (safranin, gentian violet, and orange 
G) gave useful results as a nuclear stain, but was found disappointing for the 
developing spermatozoids. 
The Behaviour of the Egg and Ventral Canal Cell. 
To determine this, more than a hundred archegonial rosettes of Poly- 
trichum formosum and P. commune were sectionized, and in no case was 
a fusion between these cells observed. On the other hand, many stages in 
the disorganization of the large ventral canal cell were seen, and the round- 
ing off of the lower cell only, to form the ovum. Ultimately the egg-cell is 
left in the lower region of the venter , and above it is sometimes seen the 
delicate transverse wall which originally separated the two cells. It seems 
probable that the appearance of fusion of the egg-cell and ventral canal 
cell observed by J. and W. van Leeuwen-Reijnvaan is due to their method 
of fixation, which they describe in detail. Before passing the archegonial 
rosettes into the fixative, they removed the involucral leaves and examined 
the rosettes with a pocket lens to determine the presence of archegonia, 
which were recognized by their necks. Under this treatment the delicate 
archegonial necks probably contract through drying a little, and squeeze the 
neck canal cells into the venter, in which situation they are described and 
figured by these observers. When the rosettes are fixed without exposure 
of the archegonia the canal-cells do not descend into the venter, and the 
