DEVELOPMENT OF THE OAPE SPECIES OF PERIPATUS. 189 
for the chromatin masses the nucleus would be quite undistin- 
guishable from the surrounding protoplasm, except, perhaps, 
by the fact that the meshes of the network (i. e. network as 
seen in section) are rather larger than in the protoplasm imme- 
diately around the nucleus. 
The most important, and at the same time most certain, of 
these observations on the nucleus of the fertilised ovum of 
Peripatus, is that the intra-nuclear and extra-nuclear reti- 
culum are both continuous with the so-called nuclear mem- 
brane. This continuity between the extra-nuclear and nuclear 
spongework is rendered still more obvious by a consideration 
of the next form. 
d. The last form I have to describe under this head is the 
spindle form (Pl. XII, fig. 11). It was met with in an ovum 
of two segments. 
The spindle is of enormous size (distance between the poles 
0:06 mm.). The protoplasmic fibres composing it are abso- 
lutely the same in appearance as the rest of the cell proto- 
plasm, and must have been largely derived from the latter. 
The chromatin is present in a very condensed form (i. e. deeply 
staining) as a number of bent rods at the equator of the 
spindle. Around the poles of the spindle the protoplasmic 
reticulum is arranged in a radiate fashion. The spindle 
appears not to be composed of simple fibres running from pole 
to pole, but of the ordinary reticulum, the meshes of which are 
very much elongated in a direction parallel to the long axis of 
the spindle. The same may be said of the fibres radiating from 
the poles of the spindle. 
The facts which are most clearly brought out by the above 
observations, and about which I have no doubt, are— 
1. The continuity of the nuclear reticulum with the extra- 
nuclear reticulum. 
2. The similarity in structure between, and the continuity of, 
the so-called fibres of the spindle in form d with the surrounding 
reticulum; and the; conclusion I have drawn from my observa- 
tions is that the nucleus of the fertilised ovum of Peripatus differs 
from the cell protoplasm only in the manner in which the so- 
VOL, XXVI.—NEW SER. fo) 
