Sexual Nuclei in Li Hum Mart agon, 453 
traversed by these threads, but the patches of cloudy 
substance, which I shall call amorphous chromatin, seem 
more numerous towards the periphery. In the larger meshes 
of the network are several spherical nucleoli of various sizes. 
The first stage which can be identified as indicating 
approaching division is the slender spirem (Fig. 2). The 
nuclei are decidedly larger than in the resting stage and their 
structure is very different. The nuclear membrane is still 
distinct, and within it is a single slender ribbon much 
convoluted and enclosing within its curves several small 
nucleoli. No anastomoses are seen, and the ribbon takes 
a uniform green colour in methyl green. The amorphous 
chromatin has entirely disappeared. No doubt it has served 
to feed the ribbon, but I have not been able to find a series of 
intermediate forms which would link the structure of the 
resting nucleus to that of the slender spirem. Transitional 
stages between slender spirem and early spindle (Fig. 4) are 
easily found. The ribbon becomes shorter and broader so 
that the convolutions are more simple. At last the nuclear 
membrane vanishes and the nucleoli disappear. The ribbon 
then falls into segments. In the stages immediately pre- 
ceding this the ribbon shows signs of a certain method in its 
twistings. I have never been able to follow it throughout its 
course on account of the small size of the nucleus and the 
number of coils within it. But the general impression left 
after examining many figures is that there is a definite 
arrangement of coils resembling that figured by Professor 
Flemming for the spermocytes of Salamandra \ 
Figures such as that shown in Fig. 4 are extremely 
common, and in the absence of any direct evidence con- 
cerning seriation I was at first inclined to consider them as 
late stages in which the segments pointing upwards were 
about to proceed to one pole, and those pointing downwards 
to the other. On being counted, however, the chromatic seg- 
ments turned out to be about twenty-four in number, whereas 
1 W. Flemming, Neue Beitrage zur Kenntniss der Zelle, PI. xxiii. fig. 2. 
