KEPliODUCTIOX OF KALPIDORH YXCHUS ARENICOL^. 565 
On the Reproduction of Kalpidorhynchus 
arenicolae (Cnghm.). 
By 
i^[arg:ai'ct Roltiiisoii, 
University College, London. 
With Plate 29. 
Introduction. 
In 1907 Mr. Cnnniiigliam described and gave a life- 
liistory of this gregarine in the ^ Archiv fiir Protistenkunde.’ 
The parasite was first noticed by Mr. De Morgan while dis- 
secting some .specimens of Arenicola ecandata in this 
laboratory. Owing to pressure of other work Mr. Cunning- 
ham was unable to give a complete account of the repro- 
duction, and he therefore suggested that I should, at some 
future time, try to find the first division nucleus with a view 
to ascertaining where the chromatin of its chromosomes 
came from. The latter half of this problem still remains 
unsolved; but after cutting many cysts into sections I did 
find the first spindle in a very early state, and I have been 
able to make one or two other observations which may prove 
to be not without interest. 
]\lETnODS. 
The cysts Avere fixed Avith various fluids, Hermann’s, 
Flemming’s, corrosive sublimate and acetic acid, Avith and 
Avithout the addition of formaline, Bonin’s picro-formol and 
Brasil’s picro-formol. The best results Avere obtained by 
using the picro-formol mixtures. The sections Avere stained 
