and Reproductive Phenomena of the Amceban Rhizopods. 463 



number ; whilst within the frustule I have not seen more than 

 four. 



In directing attention to these facts, I would lay great stress 

 on their bearing upon the question as to whether true Amoebce 

 are ever developed within the cells of the confervoid Algse. 

 For, although I have hitherto failed to trace the passage of the 

 sarcoblasts into a young Amoeba whilst yet within the interior 

 of the diatom-frustule, it is evident that if the granular bodies, 

 within and without the frustule, are identical in origin (and 

 I see no reason for questioning it), the actual witnessing 

 of the process is a mere matter of time and patience ; and it 

 must be obvious that, in the absence of a previous knowledge of 

 the origin of the intrafrustular Amoebce, the great error would 

 in all likelihood be perpetrated of regarding them as having 

 been generated from the gonidia of the Protophyte, instead of 

 from the sarcoblast of the Rhizopod. 



It is necessary to mention that the mere occurrence of a few 

 more or less colourless granular corpuscles within a capsular 

 cavity affords no evidence either as to their origin or their nature. 

 Such bodies are produced both in the animal and vegetable 

 kingdoms, and may constantly be detected within the effete 

 tests or skins of Infusoria, Eotifera, Entomostraca, and confer- 

 void Algse. In most cases, their presence is purely accidental, or 

 at all events unconnected with the reproduction of the organism 

 within whose test or cell-wall they are found. So that the 

 establishment of the fact I have just recorded teaches us how 

 great a degree of caution is requisite before we pronounce vege- 

 table products, found within the bodies of the lower forms of 

 animal life, to have been evolved there; whilst, on the other 

 hand, it exemplifies how subtle are the means whereby animal 

 germs may find their way into, and hence simulate, vegetable 

 products. 



Here then we have presented one phase, at least, of the en- 

 cystation of Amoeba, from its commencement to its completion. 

 The supplementary phenomena — namely, those dating from the 

 partial desiccation of the granular bodies now formed, to the 

 period at which they become developed into young Amoeba, 

 have been traced in my last paper on the subject (Annals, 

 Nov. 1863). In interpreting the appearances, I have only to 

 add that the abundance of the specimens, and the successive 

 stages of the process observed, render it tolerably certain, on 

 the one hand, that the protoplasm of the diatom furnishes nu- 

 tritive material to the Rhizopod during the period of quiescence 

 attendant on its encystation ; on the other hand, that the occa- 

 sional enclosure of frustules belonging to distinct genera — as, 

 for example, a Pinnularia with a Stauroneis or a Navicula — 



