120 GERM-CELL CYCLE IN ANIMALS 
one toten. The odcytes that become eggs are those 
that chance to lie at the periphery of the ovary and 
hence are in a position to derive abundant nutrition 
from the blood. The odcytes that fail to become 
eggs are not, according to De Winter, “ vitello- 
génes”’ but true abortive eggs, representing a more 
primitive stage than the nurse cells of other insects 
which have acquired, secondarily, a nutritive func- 
tion. 
On the other hand, Govaerts (1913) argues strongly 
in favor of the view that the odgonia divide differen- 
tially, the daughter cells becoming true germ cells 
(the ultimate odgonia) and true somatic cells (the 
nurse cells). He bases his position upon the condi- 
tions existing in the ovaries of certain beetles of the 
genera Carabus and Cicindela, and upon the dis- 
coveries of Giardina (1901), Debaisieux (1909), 
and Giinthert (1910) in Dytiscus marginalis. Giar- 
dina established for Dytiscus the fact that the mito- 
ses which result in the formation of nurse cells are 
differential, as theoretically postulated by Paulcke 
(1900). During the four divisions preceding the 
formation of the odcyte a single o}gonium gives rise 
to one odcyte and fifteen nurse cells (Fig. 38). A 
differentiation takes place in the chromatin of the 
odgonial nucleus, one half consisting of a condensed 
mass, the other half of large granules which corre- 
spond to the forty chromosomes of the odgonium 
(Fig. 38, A). During mitosis the chromosomes 
become arranged as an equatorial plate, and the 
chromatic mass forms a ring about it — the “anello 
