ARCHEB — ON " rALMOGL(EAN" A.LQM. 269 



Now, in the cases which I have just so briefly alluded to, more or 

 less varied as may be the accompanying conditions, simple or complex, 

 or more or less specialized as may be the accessory organization, the one 

 pervading essential circumstance in the phenomenon beyond doubt seems 

 to be the material union, the flowing into one, the simple fusion, of at 

 least two primordial cells. 



Now, what less than this is the act of conjugation in oar Cylindro- 

 cistis and Mesotaenium ? 



It may be, perhaps, answered that neither of the two conjugating 

 cells is ciliated, and that they are apparently morphologically equiva- 

 lent — that two cells only co-operate, whilst many spermatozoids may 

 take a share in the fertilization of a single oospore. 1 can only say that 

 these objections refer to conditions which seem to be in a measure acci- 

 dental, and unessential in a physiological point of view. The mecha- 

 nism of conjugation, if I may so express myself, does not require the 

 special organization on the part of the primordial cells engaged in the act, 

 which are found in Yaucheria, Sphseroplea, some CEdogonia, &c. In 

 these greater or less numbers of ciliated spermatozoids are produced — 

 ciliated, probably, because they have a distance to travel — often in mul- 

 titudes, to insure that some may ultimately find their way to the 

 oospore ; whereas in the Conjugate two cells about to conjugate lie side 

 by side, and are mostly joined by an intervening canal, formed by the 

 walls of the parent cells, through which the protoplasmic contents are 

 guided, and pass over by means of their own innate contractility, when 

 acted upon by the marvellous impulse to coalesce the one with the other. 

 Again, as to bat two primordial cells co-operating in the act of conju- 

 gation, whilst many (the spermatozoids) may unite with one (the 

 oospore) in the other cases cited, the mechanism of conjugation, if no 

 other reason, places a bar to this. I have, indeed, in such free forms of 

 Conjugate as Closterium and Staurastrum, seen three individuals conju- 

 gated, forming a single zygospore- — nay, it sometimes happens in Zyg- 

 nema that the lateral processes of two joints inosculate with a single joint 

 of a neighbouring filament, three cells thus co-operating in the conju- 

 gation. These, however, are quite exceptional, perhaps even abnormal, 

 cases. But this argument, even if adduced, I should regard as quite 

 groundless ; as it is, I presume, quite physiologically possible that one 

 spermatozoid might fertilize one germ-cell. Nay, even supposing that 

 it always required the united co-operation of several spermatozoids to 

 fertilize one germ-cell of so much greater volume than one of themselves, 

 might it not be supposed that, by reason of the more nearly or altogether 

 equivalent volume of the two conjugating cells, the force or potency 

 would be sufficient without the co-operation of a greater number, not to 

 Bpeak of the mechanical impossibility in most cases, or of the unnatural 

 dimensions which a zygospore must assume, if formed by the union of a 

 number of so comparatively large ordinary cells ? 



But, even though it be reiteration of already known facts, in pursu- 

 ance of our argument, it will be well momentarily to carry on our exarai- 



