310 LANGENBECK. [VoL. XIV. 
At this stage x and y appear smaller and at a lower level in 
surface view, as though they were being pushed inward (Fig. 
13). Sections just after this time (Figs. 9, 10) show forty-three 
cells arranged around a blastocoel, within which, at one end, lie 
two cells x’, y’ (Fig. 9). The nucleus in one of these cells may 
still be seen (Fig. 9); in the other it is no longer present. I 
have also sections of one egg (Fig. 20) showing forty-one cells 
arranged around a blastocoel, and two of the cells have spindles 
whose equatorial planes are parallel to the surface of the egg. 
(Only one of these is shown in the figure.) The question now 
arises, Do the two cells which are, after this stage, ALWAYS found 
in the center of the egg, go in by a division parallel to the sur- 
face, or are they x and y which have been pushed in during 
the later division of the other cells? Unfortunately, I was not 
able to tell whether the two cells dividing inwards (Fig. 20) 
were the cells g, # or not. Although I have cut a number of 
eggs passing from the 32-cell into the 42-cell stage, I have 
never seen spindles directed radially when x and y were present. 
I hoped by tracing the cells into the next division to determine 
whether x and y were pushed in; if these two-cells in that 
place were wanting, they might be accounted for in this way. 
I did not succeed, however, because the descendants of G4, A, 
and G*, H® take such different positions that it is impossible to 
be sure of the following generation. For instance, in one egg 
the arrangement was 
Ge He 
G* He 
G® G> H*® He 
as shown in Fig. 23. In another 
Ge 
Ge He He 
G*® G> He H* 
while in a third it was 
G* FH 
G* H# 
G> Hf? 
G*® H® 
