i Meiosis 
Premeiotic na \ 
P. M. M, M2 
Fig. 26.—Diagram to explain the course of an ordinary nuclear 
division and the relation to it of the meiotic divisions. 
The series 1-6 P M represents selected stages, in the order in which they 
occur naturally, of an ordinary nuclear division before reduction in the 
number of the chromosomes has occurred. 
The series 1,;—6, M represents the stages which roughly correspond to 
the premeiotic in the first meiotic (reduction) division. Stages 1 and 2 are 
practically identical. In 5 the longitudinal fission previously seen in 2, 
is again clearly visible. 
The series 39-62 (Mg) represents the second meiotic division. It shows 
the subsequent division of nucleus A (M)~—6,) in the series immediately 
preceding Mg. The corresponding nucleus, B, in series M, 6, is not shown, 
but its further division is exactly like that of A. 
When A (or B) in M, 6 proceeds to divide, it does so without going 
through the stages 1-2, but passes at once into A3e. The sides of each 
loop represent the early longitudinal fission of the previous series now be- 
coming effective. At 49the halves are seen in pairs and they separate in 
5o; in 62 is shown the stage at which the nuclei A) Ag are finally going back 
to a resting condition. 
