EMBRYOGENY 15 
sperm (TEXT FIGS. 17, 19). The extension of the suspensor mass 
beyond the endosp into the remnant of the nucellar cap with its 
cells full of starch (TEXT FIGS. 15, 18) suggests a possible function 
as an absorbing agent. Again a peculiar development has been 
noted as in TEXT FIG. 19, where the crowding of the surrounding 
endosperm has forced the embryo, at an early stage, farther than 
usual from the surface. The embryo has retained its connection 
with the surface layer, however, by means of a more than usually 
complex suspensor system. PLATE I, FIG. 8, shows a four-celled 
embryo and two very short suspensor cells. In the formation of a 
well-developed suspensor, Arisaema triphyllum stands alone 
among the aroids of which we have full descriptions. Pistia with 
its globular embryo and no suspensor as described by Hegelmeier 
has been taken as the type of the group. More recently Campbell 
has described Lysichiton kamtschatcense (5) and Nephthytis liberica 
(7) as producing an embryo without suspensors. In speaking of 
Anthurium violaceum Campbell (7, p. 334) says, “the egg . . . is 
attached by a broad base to the apex of the sac.” He also speaks 
of a rudimentary suspensor formed by the division of the basal seg- 
ment of the embryo in this species. This seems to be quite sim- 
ilar to Aglaonema commutatum as reported by the same author 
(6), which is said to show the embryo attached to the wall of the 
embryo-sac by a cell which might be considered a suspensor. 
Campbell also reports for Spathicarpa sagittaefolia the cutting off 
of a small basal or suspensor cell by the first division of the fer- 
tilized egg. In Arisaema triphyllum, as already stated, the first 
division produces two unequal cells, the basal and larger one of 
which is similar to that cut off by the first division in Anthurium 
and Aglaonema. But in Arisaema this cell by repeated divisions 
produces a complex suspensor system. 
Returning to the development of the embryo proper, it has 
been observed that a second and even a third transverse division 
may take place (PLATE 1, FIG. 10). The greater number of the prep- 
arations show the second division in a vertical plane, as in PLATE 1, 
FIGS. 13, 14. A second vertical division across the plane of the 
first produces a four-celled embryo. The four-celled embryo is 
loosely held together and covers the top of the suspensors as a 
disk-like cap. The later divisions have not been followed in 
