150 Davis . — Nuclear Studies on Pellia. 
remarkable centrosphere-like aggregations of kinoplasm at 
the poles of the spindles in the tetrasporangium, but these 
structures are not permanently present in the protoplasm. 
We know almost nothing of spindle-formation in the Chloro- 
phyceae, but observations on the development of zoospores 
indicate that kinoplasm may there take form and appear as 
blepharoplast-like bodies (Strasburger, ’99). The conditions 
in the Fungi of course only indirectly affect the problem of 
phylogeny concerned with the Hepaticae. However, especially 
well-defined centrospheres and conspicuous asters occur in 
the ascus (Harper, ’97), and centrosomes have been reported 
in several other groups. 
One more class of plants, the Bryophytes, remains for our 
consideration in this brief statement of our present knowledge 
respecting the aster. Of spindle-formation in the Musci 
nothing has been published, and the members of this group 
are certainly not promising subjects for study, the cells and 
nuclei being relatively small. But among the Hepaticae we 
meet with forms whose cells are admirably adapted to a minute 
examination. Farmer (’94 and ’95) studied a number of 
genera, reporting conditions of great interest. He described 
asters and centrosomes (Farmer and Reeves, ’94) for the early 
mitoses in the spores of Pellia as they germinate in the 
sporangium, and his results were confirmed by Strasburger (’95) 
from Farmer’s own preparation. Schottlander (’92), before 
Farmer, had noted centrosomes in the sperm-mother-cells of 
Marchantia , but without attendant radiations. His con- 
clusions, however, are open to criticism on account of the 
methods employed, and further study of this point is much 
to be desired. 
Of greater interest than the aster in Pellia is Farmer’s 
account (’94) of a quadripolar spindle in the spore-mother-cell 
of Pallavicinia. This unique condition is said to arise from 
a special investing zone of ‘ archoplasm ’ around the nucleus. 
The kinoplasmic material extends into the four lobes of the 
spore-mother-cell, forming a four-rayed star with the nucleus 
in the centre, each ray becoming a pole of the spindle. The 
