April 1892.] THE BOTANICAL SOCIETY OF EDINBURGH. 375 



nucleus " ; while the remaining five sexual cells (the 

 two synergidie and three antipodes) normally undergo no 

 further development. That the synergida3 may be fertilised 

 and thus play the part of true sexual cells has been proved, 

 as stated above, by the researches of Dodel and Overton. It 

 remains therefore to be proved that the antipodes are sexual 

 cells, that they, in other words, have the power of conjugating. 

 Whether they do conjugate I am unable to state definitely, 

 but as I have found in Scilla nutans appearances as shown 

 in figs. 49 a, 49 l, it is likely that they may do so. Both 

 ovules, from which these drawings were made, are fully 

 developed, the synergidte degenerating and the ova unfertilised. 

 In the antipodal halves of either ovule the cells figured are 

 seen ; in fig. 49 a the uppermost cell, which has formed a 

 paranucleolus {p n), is the sister-cell of the ovum, but 

 which of the four cells in fig. 49 h corresponds to the 

 micropylar primordial cell it is impossible to say definitely, 

 but it seems to be the cell marked {in. p. c. ?). The two 

 groups of two cells flattened against one another at their 

 point of contact in the second figure, certainly look very 

 much as if they were on the point of conjugation. 



Can we give a reason why the synergidae and the anti- 

 podes normally do not behave as sexual cells ? 



We have already seen how the syuergidse, during their 

 early development, are better supplied with food, deiived 

 from the degenerating periblem-cells, than either the egg-cell 

 or the micropylar primordial cell ; — how each synergida 

 surrounds itself with a thick membrane, and thus shuts 

 itself off from its fellow and from the rest of the embryo-sac ; 

 — how their nuclei lie at the micropylar end of each cell, 

 i.e., next the supply of food, while vacuoles are developed at 

 the basal ends. Thus, every means has been taken by each 

 synergida to procure for itself as much nourishment as 

 possible, with the result that both thrive and assume bigger 

 proportions than the egg-cell, and that both would fulfil their 

 function, i.e., be fertilised by sperm-nuclei from a pollen- 

 grain, if it was not for the supply of nourishment becoming 

 exhausted in the apical region of the ovule before the latter 

 is fully developed. This new factor changes the whole aspect 

 of matters, for the very causes which ensured the success and 

 the development of the synergidae during their early develop- 



