No. 2.] COMPARATIVE CYTOLOGICAL STUDIES . 469 
of the first pole spindle (Fig. 311) lie twelve small chromosomes, 
which stain an intense blue black with haematoxylin and have 
an oval or slightly elongate form. It remains for investigators 
working with more abundant material and with stronger micro¬ 
scopical lenses, to penetrate more deeply into these phenomena 
of the chromatin changes, but it would seem that the chromo¬ 
somes of the first pole spindle have the value of either tetrads 
or dyads. The lilac or even reddish stain of the chromatin at 
a particular period would seem at first sight to be due to the 
assimilation by the chromatin of that nucleolar substance dif¬ 
fused in the nuclear sap ; but even as probably it might be due 
to the mere penetration of this substance between the individ¬ 
ual microsomes of each chromatin thread, without any chemical 
change of the chromatin substance (Fig. 309). The red- 
staining globules in the nuclear sap, which I have assumed 
to be of nucleolar derivation, cannot be considered as meta¬ 
morphosed portions of chromatin substance, since they vary 
so considerably in size and number ; this point needs to be 
emphasized, since in some of the larger germinal vesicles no 
trace of chromatin is to be seen, and it might be thought by 
some one that these globules, which occur in such nuclei, repre¬ 
sented the supposedly absent chromatin. (Platner, ’ 89 c, had, 
in Aulastommn seen only nucleolar fragments and overlooked 
the true chromosomes.) Where in the largest germinal vesi¬ 
cles, before the formation of the pole spindle, the chromatin 
appears to be absent in the nucleus, we must assume that it 
is merely obscured by the large amount of diffused nucleolar 
substance. 
In the first pole spindle (Fig. 311), after treatment with 
Flemming’s fluid or with corrosive sublimate, the mantle fibers 
have a remarkable thickness and appear even thicker than in 
Fig. 311 ; they stain a reddish-lilac color with the haematoxylin 
and eosin stain, not a lilac blue, as do the rays of the asters 
and the cytoplasm; I could not determine whether they extend 
quite to the centrosomes. I am also unable to decide whether 
each chromosome lies upon a single spindle fiber which extends 
from centrosome to centrosome, or whether its ends are con¬ 
nected with separate fibers. The centrosomes are rather large, 
