720 THE AMERICAN NATURALIST. [Vor. XXXIX. 
has recently studied an American species of Pallavicinia and 
has failed to confirm Farmer’s conclusions. He found the four- 
rayed figure, which Farmer terms a “ quadripolar spindle," a 
conspicuous feature of the first mitosis here as in Pellia but 
there was no indication of a simultaneous distribution of quad- 
rupled chromosomes to form four daughter nuclei as reported 
by Farmer. The four-rayed figure was merely preliminary to 
the first mitosis whose spindle at metaphase was bipolar and the 
first mitosis was followed shortly by a second, so that Pallavi- 
cinia offers no exception to the essential features of sporogenesis 
as known in all groups above the thallophytes. 
Farmer (Bor. Gaz., vol. 37, p. 63, 1904) has taken exception 
to the restriction of the term spindle by Moore and myself to 
the structure found at metaphase and holds that the four-rayed 
structure is a part of the spindle apparatus. In this discussion 
he appears to avoid the issue, which is not the broader or nar- 
rower application of the term spindle, a mere matter of usage, 
but concerns the fundamental character of the mitoses during 
sporogenesis whether they are two in number and successive in 
all forms or whether Pallavicinia presents an extraordinary ex- 
ception in a distribution of the chromatin to form four daughter 
nuclei simultaneously in the spore mother-cell. Farmer (:05) 
has recently reaffirmed his view that the poles of the four-rayed 
figure in Aneura and presumably in other Jungermanniales are 
occupied by centrospheres and that sometimes a central body 
(centrosomes) may be distinguished in each. This statement 
involves again a matter of usage in which I should differ from 
Farmer for my studies and those of. Moore do not seem to me 
to justify the application of these terms to regions of kinoplasm 
whose form is so ill defined and history so transient within the 
cell. 
These disputed points which were also discussed in: Section 
IH (Amer. Nat., vol. 38, pp. 727-732, October, 1904) are of 
importance in relation to the mitotic phenomena in other periods 
of the life history of liverworts which will now be considered. 
It may be stated, however, that other investigators who have 
studied the processes of sporogenesis in the liverworts (Van 
Hook, :00; Chamberlain, :03 ; Grégoire and Berghs, :04) sup- 
