158 GERM-CELL CYCLE IN ANIMALS 
by Patterson (1912) in Graffilla gemellipara, and by 
Patterson and Wieman (1912) in Planocera inquilina. 
Patterson and Wieman have given the uterine spindle 
in Planocera careful study, and have established the 
fact that in this species it is simply a maturation 
spindle which forms near the center of the egg and 
later moves to the periphery, undergoing during 
this migration a distinct contraction. They further 
suggest that the uterine spindles described in the 
eggs of other animals are really one phase in a typical 
maturation process. 
It has thus been shown that the first maturation 
spindle in certain eggs may remain practically in- 
active for a considerable period. It should be noted, 
however, that in Copidosoma the spindle arises not 
in the fully grown egg but in very young odcytes, 
and that it appears to lack asters at every period of 
its history. While therefore this structure may be a 
precocious maturation spindle, it differs markedly 
from any other such spindle that I have been able 
to find described in cytological literature. 
The second view is that the odcyte spindle repre- 
sents a special mechanism leading to an accurate 
distribution of chromatin in the keimbahn-chromatin 
mass. The position of the contracted and condensed 
spindle, however, is not definite, since it has been 
found to occupy almost any part of the odcyte and 
to lie with its long axis parallel to the long axis of 
the odcyte, or oblique or even perpendicular to this 
axis (Fig. 46, E, G). Furthermore the keimbahn- 
chromatin does not seem to be of a definite structure, 
