164 NATOTtAL HISTORY SOCIETY OF DUBLIN. 



colourless prolongations, mostly in contact with the inner surface of the 

 hyaline envelope cell. We find, preparatory to the primordial cells under- 

 going the Protococcoid or other intermediate developmental condition, 

 that these protoplasmic elongations are drawn in. Now, except as regards 

 the length of time occupied in the process, I do not see any essential 

 difference between this and the action of the pseudopodal processes in 

 my amoeboid bodies — the one, in the ordinary course of its existence, takes 

 hours to project and again to withdraw what, with equal right, may be 

 called " pseudopodal processes," while in the other the act was momen- 

 tary. It is true that, in describing these protoplasmic prolongations in 

 the primordial cells, Cohn and Wichura* suggest that these in the 

 young Stephanosphsera adhere, here and there, at certain points, to the 

 inner surface of the envelope cell ; and that during the expansion of the 

 latter, as it approaches maturity, these prolongations of the protoplasm 

 may thereby be gradually drawn out. But one frequently sees some 

 Stephanospha3ra3 in which the primordial cells are not thus drawn out 

 into these slender prolongations ; indeed, I find them constantly so when 

 kept some time in the house in semi- obscurity , and therefore these do not 

 seem to be due to a structural peculiarity, but to the innate power of the 

 primordial cells to put them forth. Nor, again, when present, do they all 

 seem to reach the inner surface of the envelope cell, and some even finely 

 drawn out appear to project obliquely inwardly. Similar extensions of 

 the protoplasm are, in other stages of development of Stephanosphsera, 

 to be seen figured in Cohn and Wichura' s memoir, f which in the 

 course of development are again drawn in ; so also in Chlamydococcus. 

 Now, it seems to me that this ordinary behaviour of the primordial cells 

 in the development of this organism, and the action of my rapidly rep- 

 tant amoeboid bodies (precisely the same primordial cells), are mani- 

 festations of one and the same phenomenon, differing only in the degree 

 of intensity with which they are evinced. 



It may be said that the primordial cells of the mature plant do not 

 change place within the envelope- cell; but there are circumstances, even 

 though the force were more energetic than it at all can be, which prevent 

 this. The pair of fiagelliform cilia projecting through the extremely 

 minute openings in the wall of the primordial cell into the water, and the 

 majority of the protoplasmic prolongations reaching to contact with its 

 inner surface, where they doubtless for a time adhere, tend to suspend 

 the primordial cell in its place. But even when these are not fully ex- 

 tended, and besides the slowness and comparative feebleness of the process, 

 the prolongations existing at opposite ends simultaneously and the con- 

 tents being of a compact and comparatively firm character, not loose and 

 disintegrated as afterwards, as evinced by the constancy in position of the 

 two " chlorophyll- vesicles," there is no flow in any direction of the 

 contents, nor any reptant motion. There is, I think, to some degree, a 

 certain amount of foreshadowing, as it were, of the differentiation of the 



* " Ueber Stephaenosphaera," loc. cit., p. 16. 

 f Ibid., Tab. B, 12, a, b, c. 



