Davis . — Nuclear Studies on Pellia. 15 1 
chromosomes, four in number, are organized in the nucleus, 
and by a doubling division are increased to sixteen as mitosis 
proceeds. Four chromosomes then travel along each division 
of the four-poled spindle. Finally the four rays of the star-like 
figure break apart at the centre, the kinoplasm ( c archoplasm ’) 
in each contracting, with its group of chromosomes, and 
shortly afterwards the four daughter-nuclei are organized. 
In a note and an extensive paper which appeared in the 
following year Farmer (’95 a and ’96 b) considers a number of 
species of Hepaticae distributed through several genera. 
With respect to the quadripolar spindle he did not find it 
very generally present. There are two successive divisions 
closely following one another in the spore-mother-cells of the 
Marchantiales (. Fegatella , Fimbriaria , and Plagiochasma) and 
the Ricciales. Each mitosis is entirely distinct, but in some 
instances the first presented the arrangement of the chromo- 
somes known as heterotype. Among the Jungermanniales 
there was some diversity. Pallavicinia , Fossombronia , Pellia , 
Scapania , Cephalozia , Lophocolea , Frullania , and Aneur a have, 
according to Farmer, quadripolar spindles at least in the 
prophase of mitosis, but sometimes bipolar spindles result 
from the apparent coalescence of the four original centres. 
In Riella there is never any indication of a quadripolar spindle, 
but instead, two mitoses following one another, with spindles 
of the usual bipolar type. However, the latter condition, 
identical with the usual order of mitoses in the spore-mother- 
cell, is believed by Farmer to have arisen from the four-poled 
spindle. He considers certain species of Pellia , Aneur a , 
Scapania , and Cephalozia as presenting transitional stages 
in the process whereby the four centres of the quadripolar 
spindle, fusing in pairs, form a spindle of the bipolar type. 
The quadripolar spindle is then regarded by Farmer as 
well established for the spore-mother-cell of Pallavicinia , and 
as present but not permanent in the prophase of the homologous 
mitoses in many other Jungermanniales. In the latter forms 
it is replaced by the two successive mitoses almost universally 
present in spore-mother-cells, but Farmer believes these to 
