ARCHER ON STEPHANOSPH^EBA PLTJVIALIS (COHN). 159 



rously active Amceba-like bodies with the just previously absolutely 

 quiescent primordial cells of the Stephanosphoera — nay more, in watch- 

 ing the transformation of the latter themselves into the reptant amoeboid 

 bodies, putting a parasitic development wholly out of the question : it 

 will readily be believed, I say, that my astonishment was beyond mea- 

 sure great, in actually witnessing with my own eyes this, at first sight, 

 sufficiently startling phenomenon. What ! a plant, an undoubted true 

 chlorophyll-containing, by cellulose externally bounded, Alga, become 

 metamorphosed into an animal ! For my part, indeed, even after wit- 

 nessing the wonderful change now mentioned, I could not acquiesce in 

 such an assumption ; and so far as I can see, in my humble judgment, 

 those who might be disposed thus to understand it would greatly mis- 

 interpret the phenomenon. 



I shall try to describe these remarkable bodies more fully. 



I have spoken of the primordial cells of these examples having be- 

 come retracted from the inner wall of the hyaline sphere, and having 

 acquired a rounded form within it, as if possibly about to undergo either 

 the ordinary process of self- division, or it might be the Protococcoid or 

 the Chlarnydomon as-like developmental condition before alluded to, the 

 movement of the globe itself having ceased. But, upon a closer examina- 

 tion of certain of these, there was to be seen a gentle hyaline convexity 

 or expansion gradually being extended from the green margin of the pri- 

 mordial cell, and again slowly drawn in, whereupon another similar 

 projection took origin close beside the place where the first had vanished. 

 This again receded, to be followed perhaps by another in the same or 

 nearly the same situation as the first, or at all events near thereto 

 (Plate II., Fig. 3). Presently the extension and withdrawal of these hya- 

 line prolongationsbecame more frequent and vigorous, while they appeared 

 to be chiefly confined to one hemisphere. Afterwards the mass became 

 somewhat elongated, the hyaline projections more lobose and more 

 changeable, and finally the primordial cell assumed somewhat the out- 

 ward characters figured for Amoeba Umax (Plate II., Figs. 4, 5, 6). The 

 general contour of the so far changed primordial cell, supposing it at rest, 

 might now be described as broadly clavate or pyriform, the narrower 

 end tapering very considerably, and bluntly pointed. From the consi- 

 derably expanded upper end only, the lobate pseudopod-like extensions 

 were projected ; and of these generally not more than two or three existed 

 at one time, so that this margin mostly thus presented a trifid or bifid 

 outline. The narrow end seemed to be nearly if not quite rigid; at 

 least, neither from it nor from the sides were any of the pseudopod-like 

 extensions put forth, whilst the narrow extremity itself seemed to pos- 

 sess somewhat of a slightly granulated appearance. All traces of the 

 conspicuous pair of " chlorophyll- vesicles" (for as perfectly homologous 

 with the bodies so-called, in other algae I regard them) had vanished — 

 the green contents, keeping their colour, had become more decidedly gra- 

 nular ; the granules, which were very crowded and abundant, and of 

 varying sizes, the variations however taking place within very narrow 



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