Hum aria rutilans , Fries. 
47 
The second mitosis begins by the formation of sixteen chromosomes ; 
these become grouped on the spindle but do not acquire the lozenge shape 
of the first division. V-shaped figures only are seen, and later much drawn 
out filaments ; there seems reason to believe that the V breaks at its apex 
as in the homotype division of Phanerogams. 
The third division differs sensibly from the other two. A fine spireme 
is formed and divides into sixteen curved chromosomes, which become 
grouped in an equatorial plate. Guillermond states that, owing to the 
delicacy and large number of the chromosomes, the method of splitting 
could not be observed. In the late metaphase and early anaphase the 
chromosomes are elongated along the threads of the spindle, and directed 
towards the poles. In this division, as in the first and second, the number 
of chromosomes at each pole is given as sixteen. 
I have been able, in the present investigation, to confirm Guillermond’s 
observations with regard to the first and second mitoses. In the early 
prophases of the first division, and between the synaptic contraction and 
the appearance of the mature chromosomes, as described by him, I have 
been able to observe some further stages, thus bringing these divisions into 
line with the meiotic processes as described by Farmer and Moore. The 
first contraction and the longitudinal fission of the spireme (in part at least) 
take place before the fusion in the ascus, and the changes thus begun 
continue, apparently without interruption, in the definitive nucleus. The 
difficult question of seriation is here specially clear ; it seems obvious, for 
instance, that such a stage as Fig. 17 , where the ascus nuclei each show 
a few paired threads, must precede that shown in Fig. 19 , where the 
spireme of the definitive nucleus is double throughout its length. Synapsis 
sets in, loops are formed, their sides approximate, and the whole loop 
constitutes a bivalent chromosome. On the spindle of the first division the 
two limbs of the chromosome break apart, thus separating unlike portions 
of the spireme. In the second division the longitudinal split takes effect. 
Thus here, as in Lilium candidum and the other forms described by 
Farmer and Moore, the first meiotic division is diaschistic, and brings about 
a reduction in the sense of Weismann. 
The Third Mitosis. 
The processes in the ascus are confused, as compared to the meiotic 
phase in other organisms, by the introduction of a nuclear fusion. 
The number of chromosomes in the vegetative divisions directly pro- 
ceeding meiosis has been constantly found to be the same as in the first 
division in the ascus. This was ascertained by Harper for Pyronema (30) 
and Phyllactinia (31), both forms with normal sexuality, and in the present 
instance for Humaria rutilans . 
In Humaria rutilans , at least, the heterotype division is begun before 
