364 K. MASUI: 
49), while the cells of the other half have only the small chromatin masses 
(Figs. 48, 50). We thus have a phenomenon of dimorphism in this stage in 
regard to the existence of the.chromatin nucleolus. In the cells where this 
latter structure occurs, it is usually found closely located to the nuclear wall 
(Fig. 49). 
Both the idiozome and the mitochondria are distinctly seen in this stage 
(Figs. 49, 50).. But the centrosome is rarely seen within the idiozome (Fig. 
49). 
The second reduction division :—In this division all the chromosomes arrange 
themselves to form the equatorial plate, where they show a tendency to gather 
into a mass, as in the case of the first reduction division. But in fairly good 
stained preparations I have been able to find the accessory chromosome and 
also make out the ordinary ones individually (Figs. 52—54). In consequence 
of the first reduction division one half of the equatorial plates of this division 
contains eighteen chromosomes, while the other half has besides these one 
accessory chromosome (Fig. 52). 
The accessory chromosome is sometimes placed apart from the ordinary 
chromosomes in the equatorial plate, and is usually larger than these (Fig. 52). 
The second pairing of the chromosomes in the second reduction division 
is reported to oceur: by Jorpan (11) in the opossum, by Guyer (’10) in 
man, and by WoDsEDALEK (713) in the pig. In the horse WopsEDALEK (14) 
found that the second pairing of chromosomes takes place immediately after the 
first division. His reason for the occurrénce of this phenomenon is, that “ the 
resulting nine chromosomes are not one half the size of the original chromo- 
somes of these cells, but exactly of the same size and apparently quadrivalent.” 
I have failed to find the second pairing of the chromosomes in my preparations. 
But sometimes incomplete fusion of the chromosomes is seen to occur, as 
JORDAN reported in the opossum, and in such cases occasionally fourteen or 
more chromosomes can be counted (Figs. 51, 54). Whether this represents 
the secondary pairing, I am not able to determine. Fig. 57 represents an 
anaphase of the second reduction division, showing no lagging or advancing 
chromosomes such as GutyER (10) has described for man and WopsEDALEK 
(14) for the horse. In this division the accessory chromosome is divided at 
the same time with the ordinary chromosomes (Figs. 55—58). 
