On the Occurrence of Centrospheres in 
Pellia epiphylla, Nees. 
BY 
J. BRETLAND FARMER, M.A., 
Assistant Professor of Biology , Royal College of Science , London , 
AND 
JESSE REEVES, 
Marshall Scholar, Royal College of Science, London. 
With Plate XIV. 
I T is a well-known fact that the spores of Pellia epiphylla , 
like those of some other Liverworts, germinate while 
still enclosed in the sporogonium, and that long before the 
wall of the capsule ruptures, the spores have become multi- 
cellular bodies. The spores of Pellia , when in this condition, 
afford excellent material for the study of the karyokinesis, 
owing to the large size of their nucleus and the relatively 
small number of its chromosomes. But the special interest 
which attaches to them lies in the singular degree of clearness 
with which the attraction-spheres (or centrospheres) are 
differentiated, and in the facility which is thereby afforded 
for the study of these structures in their relation to the 
process of nuclear division. 
For the purpose of this investigation, fruiting plants of 
Pellia were gathered during the winter, and were preserved 
[Annals of Botany, Vol. VIII. No. XXX. June, 1894.] 
Q 2 
