On the Change of Vegetable Protoplasm into Actinophrys. 261 



globules, and both forms make their way to the confines of the Spi- 

 rogyra-coW, which they ultimately pierce, develope their contents, 

 and discharge them in the following manner : — 



On reaching the cell-wall, each form puts forth a minute papillary 

 eminence, which, having passed through the wall, expands into a large 

 sac, or bursts at its apex. Following the isolated form first, this then 

 gradually drags four-fifths or more of its bulk through this opening, 

 sometimes so much as only to leave a little papillary eminence in it, 

 which then makes the portion of protoplasm look as if it were entering 

 instead of escaping from the Spiroggra-ceW ; the internal contents of 

 this protoplasm then become more defined and granular, the gra- 

 nules assume a spherical form respectively, they evince a power of 

 locomotion, and the originally flexible pellicula having become a stiff- 

 ened cyst, with a more delicate one within (as in the process already 

 detailed), assumes a slightly conical form, which giving way by a cir- 

 cular aperture at the apex, allows the granules to pass into the water, 

 when they are seen to be monocihated Monads ; each consisting, 

 apparently, of a film of protoplasm expanded over an oil-globule, and 

 bearing a single cilium. The contents of the tubular form, on the 

 other hand, undergo the same changes, but the tube becomes dilated 

 into a pyriform shape within the Spirogyra-ceW ; and when the Monads 

 are ready to lead an independent existence, the end of the papillary 

 eminence, which has been projected some little distance beyond the 

 cell-wall into the water, gives way, and thus they also escape. 



In another form of this tubular extension, the inner delicate cyst 

 expands into a flask-like or globular shape, beyond the papillary 

 eminence, outside the cell-wall, and retains the protoplasmic contents 

 here until they are ultimately developed into Monads. These, which 

 are much larger than the Monads developed by the other processes, 

 on issuing, mo,ve about rapidly for some time by the aid of a strong 

 cilium carried in front like that of Astasia, and then become stationary ; 

 the vesicula or "contracting vesicle," which does not appear before 

 they leave the cyst, now becomes very active, the cilium is gradually 

 diminished in size and altogether disappears, and the Monad passes 

 into a Rhizopodous, reptant state, which afterwards becomes Actino- 

 phorous, and finally assumes a form undistinguishable from that of 

 Actinophrys Sol. 



Up to this point the author had been able to follow this trans- 

 formation, and although he had not actually seen the Actinophorous 

 form enclose particles of food, yet he deemed the form itself sufficiently 

 significant to guarantee this induction, since he had never witnessed 

 a Rhizopod of the kind without attacking everything living and dead 

 that it could overcome and turn into nourishment ; besides, such a form 

 could obtain sustenance in no other way. If this was not satisfactory, 

 it was not difficult to conceive, that what the portions of protoplasm 

 in an Actinophorous form would do within, they would do outside 

 the cell of Spirogyra ; and it had been shown, in the first process 

 detailed, that inside the cell they enclosed chlorophyll, and finally 

 ejected the refuse in the manner of Amoeba. Lastly, the Monads 

 which are developed by a similar process in the Characece are fre- 



