306 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



The densely granular cytoplasm of the antipodal cells 

 does not fill them uniformly, but there are usually present 

 large vacuoles (fig. 28). The first division-walls in the 

 antipodals of S . simplex are vertical, so that the mass has 

 the form of a disc, but later transverse and oblique divisions 

 may also occur, although the majority of the walls are ver- 

 tical and the cells become a good deal elongated (fig. 30). 



As the seed grows older the antipodal cells begin to show 

 signs of disintegration, but in no cases where sections were 

 made had they entirely disappeared, and traces of them 

 probably persist even in the ripe seed. 



The earlier stages of the antipodals were studied also in 

 S. Gi'eenit iind S. enrycarpum, but material was not avail- 

 able for the later development which is probably not entirely 

 like that in S. simplex. In S . Greenii the antipodals at the 

 time the ^^^ is fertilized are, as we have seen, much more 

 conspicuous than in S. simplex. They are also differently 

 arranged, not usually lying in the same plane, but one of 

 them being above the other two (fig. 33). In one instance 

 (fig. 16) there was present above the three antipodal cells a 

 large cell which looked like a fourth antipodal, but as this 

 was the only case seen, there was no clue as to its origin. 

 Otherwise the embryo-sac appeared to be entirely normal. 

 In this species ( S. Greenii) the polar nuclei remained sep- 

 arate, although often in close contact (fig. 20) until after 

 the fertilization of the ^^'g, and in this respect it differs 

 from S . simplex and probably from S . eitrycarpiim. There 

 is also much greater variation in the size of the embryo-sac 

 in S. Greenii than in S. simplex. As a rule the ^gg and 

 synergidas are larger also than in S. simplex and sometimes 

 the former show a reticulate appearance in the cytoplasm, 

 due to the presence of numerous vacuoles (fig. 18), an ap- 

 pearance which was not seen in the specimens of the latter 

 species. The embryo-sac in S. Greenii is relatively nar- 

 rower than in S . simplex, and there are three or four layers 

 of cells at the apex of the nucellus, which is also larger than 

 in that species. As we have already stated, the antipodal 

 cells, before the fertilization of the ^gg, are noticeably 



