3<D2 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



really absent. Where they are uninjured (fig. 12) they 

 may usually be seen to be arranged in the same plane and 

 are very shallow, projecting only very slightly into the 

 cavity of the embryo-sac. The cytoplasm of these cells is 

 finely granular but does not readily stain at this stage. The 

 nuclei are very small and inconspicuous, and it is sometimes 

 difficult to demonstrate them at all. In no case did they 

 stain readily with the usual reagents. 



In S. Greenii the appearance of the antipodal cells is 

 somewhat different and this resembles more those of other 

 Monocotyledons (fig. 21). The base of the embryo-sac is 

 here prolonged into a narrow cavity within which lie the 

 antipodal cells. These are not usually in the same plane, 

 but one of them lies above the other two, to which it bears 

 much the same relation that the egg-cell does to the syner- 

 gidae. The antipodal cells in this species are much larger 

 than in S . simflex, and the cell contents denser, and the 

 nuclei are larger and readily demonstrated, as they stain 

 without difficulty. 



So far as my observations go upon S. longifolium and S. 

 eurycarftum, they are more like S. Greenii than S. sim- 

 plex in the form of the antipodals, although S. longifolium 

 is to some extent intermediate in character. 



III. Fertilization. 



The small size of the pollen-spore and nuclei is not 

 favorable to a study of the details of fertilization, and 

 although in several instances the pollen-tube was detected 

 within the embryo-sac, nothing was observed which indi- 

 cated that the fertilization was in any way different from 

 that of other Angiosperms. The pollen-tube after reach- 

 ing the micropyle pushes down between the cells of the 

 nucellus, which are not injured by its passage. On entering 

 the embryo-sac, it apparently comes into close contact with 

 one synergid, which is probably destroyed in most cases, 

 although this is not necessarily the case, as in one instance, at 

 least, the end of the pollen-tube was seen within the embryo- 

 sac, although both synergidae were still intact. The very 



