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1904] LEWIS: ANOMALOUS DICOTYLEDONS 129 
PODOPHYLLUM PELTATUM. 
The mature embryo sac does not differ in any important par- 
ticulars from that of typical angiosperms. _ The fecundated 
egg cell increases appreciably in size, becoming slightly elon- 
gated. The first division wall is transverse, and the two cells 
thus formed elongate rapidly, especially the one which is to form 
the suspensor. At this stage (jig. 7) one synergid is still to be 
“seen near the embryo, but it does not persist for any length of 
time, as it was not observed in older stages. At this time sev- 
eral endosperm nuclei are seen scattered about within the embryo 
sac. The antipodal cells are distinct, but they soon begin to 
disintegrate and are not found in the stage represented by fig. 5. 
The eight-celled embryo (fig. 2) is club-shaped, and the sus- 
pensor is rather long, consisting of two or three cells. The body 
of the embryo soon becomes broadened (fig. 3), and at the stage 
shown in fig. g it is almost spherical. Growth now takes place 
most rapidly in the longitudinal direction, and at the same time 
the suspensor becomes somewhat thickened, its cells dividing 
longitudinally (figs. 5, 6).. The embryo may now be well 
described as pear-shaped, although there is some variation in 
form at this stage. In some cases one side seems to grow more 
rapidly than the other, and an unsymmetrical form results (fig. 6). 
From the study of a large number of preparations, both longi- 
tudinal and cross-sections, it is highly probable that fig. § rep- 
resents the typical shape of the embryo shortly before the 
beginning of the development of the cotyledonar primordium. 
At this time the endosperm fills the entire embryo sac, except a 
small cavity around the embryo, which is partly filled by mater- 
ial from broken-down endosperm cells. 
The origin and development of the cotyledons is peculiar. 
In typical dicotyledons the cotyledons are supposed to have their 
origin as two entirely separate and opposite ridges of tissue, 
standing at the same level, at the broadened distal end of the 
embryo, so that if cross-sections be made through the base of 
the cotyledons they would be separate at both sides in the first 
section in which they appear. Although this mode of origin 
has been assumed by certain writers, it seems that comparatively 
