CRUCIANELLA 47 
is a specialized portion of the ovule which is especially concerned 
in secreting starch, of which a very large amount is present, while 
it is at the same time absent from the rest of the ovule. 
At the base of the archesporium the cells of the chalazal tissue 
appear, in a very early stage, just as the remainder of the cells of 
the ovule. As the integument develops, however, and therefore, 
as the archesporial cells increase in size, these chalazal cells take 
on a different character (c.c., figs. 7, 9 and 13). From being 
small cells with a rather scant supply of cytoplasm, and relatively 
small nuclei, they become larger, their nuclei grow, and they be- 
come densely filled with cytoplasm. This appearance they main- 
tain during the periods of growth of the archesporial cells, of their 
division into megaspores, and of the subsequent elongation of the 
tetrad masses. At the close of the activity of the latter the chal- 
azal cells lose their supply of cytoplasm and return to the condi- 
tion of the rest of the cells of the ovule. 
We may therefore interpret them as physiologically active in 
the nutrition of the archesporium. Similar specialized chalazal 
cells have been described in many forms, more recently, however, 
in Polypompholyx * and in. Stylidium.t 
The embryo-sac cell moves rapidly along the micropylar canal, 
and as it moves forward the integumental tissue closes behind it. 
The course taken may readily be traced by the more deeply stain- 
ing cell walls of those cells lying next to the canal. The division 
of the embryo-sac cell follows the usual order, as heretofore de- 
scribed. 
In this genus, however, the development of the embryo-sac is 
marked by the very sudden disappearance of the antipodal cells. 
Of all the preparations made, in not one have all three of the anti- 
podals been seen, although they are developed, as indicated in 
fig. 21, ant. The polar nuclei have been seen, and several 
cases have been found where one antipodal nucleus appeared 
normal. All the evidence indicates, therefore, that the sudden 
death of these nuclei is a character of the genus. It must however 
be noted that the antipodal end of the embryo-sac extends some 
* Lan . K. Untersuchungen über gp" Anatomie, und Samenent- 
wicklung v von een und Biblis gigant Flora, 88: 149-206. 1901. 
f s, G. P. Beiträge zur Kenntniss de eg Flora, 87: 313-354. 
1900. A 
