1899] STRUCTURE OF THE EMBRYO-SAC 163 
é.g., Philodendron, the embryo is smaller and surrounded by 
abundant endosperm. 
SUMMARY AND CONCLUSIONS. 
In both Sparganium and Lysichiton there is a normal multi- 
plication of the original three antipodal cells, although the type 
of these cells is quite different in the two genera. In Sparganium, 
at least in S, simplex, the number of antipodal cells becomes very 
great, in extreme cases 150 or more, thus far exceeding that of 
me other known plant. The nearest approach to this is found 
im certain Graminee, where the form of the antipodal cells 
may be also much like those of Sparganium. 
Ls extraordinary development of the antipodal cells in 
'ganium, however, is secondary, and dependent apparently 
"pon the fertilization of the egg-cell. In the unfertilized embryo- 
“acy the antipodals are unusually small and inconspicuous, and of 
the usual number. There is no evidence that the nuclei of the 
antipodal cells divide otherwise than by karyokinesis. 
b In Lysichiton the antipodal cells probably never exceed ten, 
. a become extremely large and the nuclei reach enormous 
aig Here, also, no direct division of the nucleus could 
the = . but indications of degeneration were observed in 
fragment. nud and it is possible that there may be, finally, a 
cells of Bi like that found in the multinucleate antipodal 
Lysichito oe lants. The character of the antipodal cells in 
indeed i 'S quite different from those of Sparganium, and, 
resemble % those of any other described angiosperms. They 
in which at perhaps, such Composite as Senecio and Aster, 
ais have been described numerous antipodal cells 
be also a multist endosperm. In these composites there may 
Cells, 'plication of the nuclei of the individual antipodal 
Spa 
It is ey; 
's evident that we can no longer regard the antipodal cells 
as Mere : 
that Pd oes of the primitive prothallial tissue. It is true 
be Y Pro ably represent this tissue, but that they may still 
of j i 
'Mportance Physiologically is amply shown both by their 
