from the Cell-contents of the Characese. 21 



in the spore-capsule or pass into an ovarian sac and develope its 

 progeny much in the same manner as we have seen the " gonidial 

 cells '' in the internode of Nitella. At all events^ the hole by 

 which the Astasia entered was visible, and from its minuteness 

 indicated a very minute size of the Astasia originally compared 

 with that which it presented when I saw it. 



Again, from Stein's valuable observations on the development 

 of VorticellcB (Ann. and Mag. Nat. Hist. vol. ix. 1852, p. 471), 

 and latterly my own observations on this family, I can easily 

 conceive, from the extreme minuteness with which the germs 

 might leave the ovary of Vorticella, their rapid development 

 under favourable circumstances, and their multiplication by fissi- 

 paration and gemmation, even when barely changed from their 

 larval or infant, monadic form, how accidental holes may exist in 

 the internode of Nitella, or in the cell of Spirogi/ra, Cladophora, 

 or any other filamentous or thalloid Algae, large enough to 

 admit such germs and gemmse, and yet pass unnoticed by the 

 microscopist, though not by the voracious young of Infusoria. 



Whenever a cell in the filamentous Algae shows by derange- 

 ment of the granular chlorophyll or gonimic contents that its 

 functions have ceased or become interrupted, several gonidia 

 similar to those developed in the cells of Nitella may be seen 

 swimming about it and trying to get into it, which they do 

 immediately the cell-wall gives way, and then fixing on its 

 mucus-contents devour them. 



All this seems to point out that the so-called gonidial develop- 

 ment within the cells of Nitella is anything but spontaneous, 

 while it favours the view which I have now taken, that it is 

 infusorial. 



But as we see the fragments of the contracted chlorophyll- 

 bands of Spirogyra retaining their freshness and greenness while 

 wrapped in their mucus, for weeks after the cell-wall has passed 

 into dissolution, a question may suggest itself, whether the con- 

 tents of a resting spore when quickly swallowed by an infu- 

 sorium which dies soon afterwards, might not germinate to a 

 certain extent, under such circumstances — the sac of the infu- 

 sorium supplying the place of the capsule of the spore. If so, 

 indeed, then an infusorium would after this manner appear to 

 develope a plant. On the other hand, if the chlorophyll turns 

 brown, that may be considered a sign of the death of the spore- 

 contents ; and if anything arise out of this, it must be viewed as 

 the progeny of the infusorium, such as the so-called "gonidia" 

 appear to be which I had described above as developed from the 

 cell-contents of the Characese. 



This " postscript " will not invalidate the facts in my paper, 

 although it may affect the reasoning, from tending to change 



