SHERARDIA ARVENSIS 33 
proportion (pl. 6, fig. 15). The two small antipodals are con- 
cavo-convex, and are set upon the endosperm cell as a cap. They 
are densely filled with food materials. The third antipodal is 
longer relatively than in either Vaillantia or Callipeltis, and is 
scantily supplied with cytoplasm. The distal end is formed into 
a club-shaped swelling, and is buried in the mass of disintegrated 
megaspores. The swollen end is filled with a tenuous and finally 
granular cytoplasm. 
The endosperm nucleus lies in the definitive embryo-sac 
against the egg, into which position it has moved from a distant . 
position where fusion of the polar nuclei takes place (7. 6, figs. 
IS; 10, t7). 
The development of the embryo proceeds by the formation of 
transverse walls, until about a dozen cells in linear arrangement 
have been laid down. All but the terminal cell form then the 
suspensor in which two distinct regions are to be recognized. The 
micropylar region is composed of larger vacuolated cells, which 
grow out laterally into the endosperm forcing their way between 
the cells. The nucleus lies in the concavity of the outgrowing 
haustoria just as is known to occur in young root hairs )۸/ 6, 
fig. r9). The proximal portion of the suspensor is composed of 
very short disc-shaped cells, which, while the embryo is young, 
retain that form. As the embryo becomes older, the more distal 
of these elongate, and some grow out into haustoria. "When the 
endosperm has reached its maximum size the laying down of re- 
serve cellulose begins in the peripheral cells first, and these cells 
become unfavorable for the absorption of food by the suspensorial 
haustoria. That portion of the suspensor, therefore, which comes 
to lie in the region of cellulose formation degenerates par: ۷ 
with the thickening of the cellulose layer. The function of ab- 
sorption thus given up by the more distal part of the suspensor is 
then taken up by the more newly formed haustoria. The suspen- 
sor becomes loaded with food which is gradually passed on to the 
embryo (X. 6, fig. 21). 
In the development of the embryo proper there is correspon- 
dence with the process as described for Callipeltis. One feature 
appears somewhat different, namely, that the longitudinal division 
of the terminal cell is followed by transverse division of its quad- 
