The Morphology of Ruppia Maritima. 139 
however. If they were, it is evident that a tetrad similar to that 
in Ruppia would have resulted. The upper daughter-cell with its 
two nuclei now becomes disorganized, and the lower cell becomes 
the embryo-sac, its nuclei producing directly the embryo-sac nuclei. 
Zostera marina forms three megaspores, according to Rosenberg 
(1901, I, p. 9), the lowest functioning. The uppermost, however, in 
his Figure II looks much like Figure 51 of Murbeck (1902), and 
like many of my own preparations, gives indications of two cells 
obliquely arranged. 
In Zannichellia the state of affairs is surprisingly different. Ac- 
cording to Campbell (1897, pp. 45, 46), a row of three cells is 
formed, of which the uppermost becomes the functioning megaspore. 
Since this is so strikingly diverse from what takes place in Ruppia, 
Zostera and Potamogeton, it would seem as if it needed confirmation. 
The functional megaspore now proceeds to the forrnation of the 
embryo-sac by a series of stages which are quite in line with 
those which have been found to be so remarkably constant among 
the Angiosperms. PI. XII, fig. 82 shows the megaspore nucleus 
in process of division, while Fig. 83 discloses the resulting two 
nuclei, one at each end. Fig. 84 shows the four nuclei coming 
from these two. Fig. 85 represents a mature embryo-sac with 
synergidae and egg of characteristic form and structure. The 
antipodal cells are always three in number, their nuclei being sur- 
rounded by a definite layer of cytoplasm and apparently by a thin, 
membranous wall. Often they appear rounded in form (PI. XII, 
fig. 85) and again angular (Fig. 86), in the latter case showing 
clearly their relations to each other. They resemble strongly those 
figured by Murbeck (1902, fig. 53) in Ruppia rostellata and by 
Campbell (1897, fig. 109) in Zannichelha palustris, and like them 
are situated in a small pouch at the base of the embryo-sac. 
A peculiarity of these antipodals is the conspicuous blue color 
of their nuclei with the triple stain, showing an unusual tint of the 
blue, and possibly indicating degeneration. Thus they are strongly 
contrasted with adjacent nucellar nuclei and may be readily dis- 
tinguished. They were not observed to divide, however, as in the 
case of certain recently investigated monocotyledons. Apparently 
their life is short, for they disappear in stages slightly older than 
Pl. XU, fig. 85. 
Mate GAMETOPHYTE 
Since my studies of the male gametophyte of Ruppia maritima 
agree closely with those of Murbeck (1902), it would be useless here 
Trans. Conn. Acap., Vol. XIV. 10 DecEMBER, 1908. 
