WALTER P. THOMPSON 
eye in young fruits. Most of the growth takes place downwardly 
aned laterally. Figure 59 shows a whole sac with young endosperm 
at the bottom and the fertilized egg at the side. The endosperm 
never grows much higher than this. Figure 72 shows a later stage 
and one w^hich is often found. 
It is plain from this description that Lotsy's statement is correct 
that at a certain time there is a cellular mass at the bottom of the 
sac while there are only free nuclei above. Coulter (7) thought 
that Lotsy had mistaken the peculiar pavement tissue in the nucellus 
(page 21) for tissue within the sac. Lotsy was in error, however, in 
stating that this cellular tissue is present before the pollen tube enters. 
As w^e have seen it does not develop until the male cells are within 
the sac, though I am not prepared to say that compartments are not 
present before the actual fusion of egg and sperm has taken place. 
Not having seen the actual fertilization I cannot say with certainty 
at what stage of endosperm formation it takes place in this species. 
But I have frequently observed young fertilized eggs in sacs in which 
compartments had already formed. It seems that the formation of 
compartments and fusion of endosperm nuclei go on concurrently 
with fertilization. Lotsy thought that the female gametophyte of 
G. gnemon represented an intermediate condition between that of 
Gymnosperms and Angiosperms in that at fertilization time the 
endosperm w^as partly cellular and partly free-nucleated. Although 
this gametophyte does represent an intermediate condition, it is 
much more like that of Angiosperms than Lotsy believed, because 
when the pollen tube enters it contains only free nuclei and eggs. 
The free nuclei in the upper part of the sac above the region of 
cell formation take no part in the production of endosperm. Except 
in the immediate vicinity of the fertilized egg they all disintegrate 
more or less rapidly. Those which surround the fertilized egg in- 
crease in number for a time and form a dense, deeply staining mass, 
which is well defined (fig. 53). I have occasionally observed the 
formation of compartments here similar to those at the bottom. The 
function of these nuclei and of the protoplasm in which they lie, 
appears to be the nourishment of the fertilized egg. But sooner or 
later these also degenerate leaving the fertilized egg alone in the 
cavity of the embryo-sac some distance above the endosperm. 
(h) G. sp. J J.' — In this species and similar ones endosperm formation 
takes place in a somewhat different manner. As soon as the pollen 
