488 
L. nOXCASTEH-ANI) .T. GKAA'. 
soines and of vesicles is due in part to the fact that the 
vesicles are being formed at the stage at which the counts 
were made, and in some nuclei others might still have been 
produced ; and as regards chromosomes, to the fact that at 
this stage they show a strong tendency to become clumped. 
Tiie counts in Table I were made by eye ; the nutnber of 
vesicles in each case may be regarded as trustworthy, of 
chromosomes only approximtite. 
Table I. — Numbers of C h rom o som es and Vesicles in 
l^rophase Fig 
u r e s 
(first division). 
a c u t u s ? 
e s c u 1 e n t u s . 
Chromosomes. 
Vesicles. Chromosomes. 
A'esieles. 
31 
12 
29 
G 
29 
9 
35 
2 
32 
() 
32 
2 
3 1 
2 
29 
3 
33 
.■> 
O 
31 
0 
28 
1 
32 
3 
33 
1 
32 
4 
31 
() 
32 
7 
28 
2 
31 
o 
O 
31 
3 
32 
3 
33 
5 
V at first believed that 
each vesicle was 
formed from 
chromosome which was entirely used up in the pi’ocess, but a 
detailed examination and comparison of different stages 
makes this view untenable. AVe believe that the vesicle 
formation may be explained as follows : In the late prophase 
stages, when the normal chromosomes are beginning to 
split longitudinally, some of the chromosomes, instead of 
splitting', tend to swell up and form vesicles as the normal 
chromosomes do in the late anaphase stage. Every gradation 
may be found between chromosomes which behave normally 
and those which are completely converted into vesicles. 
