462 Dr. G. C. Wallich on the Distinctive Characters, Habits, 



within and without their bodies, although energetic when the 

 encystation commenced, are succeeded by a state of complete 

 quiescence afterwards. But, even at this stage, clear proof of 

 vitality is afforded by the gradual segregation of the granular 

 particles into masses, which ultimately become spherical and 

 apparently identical with the sarcoblasts (PI. VIII. fig. 14). Of 

 course, if identical, my view as to these bodies being formed from 

 the granular particles of the endosarc generally, rather than from 

 the repetitive subdivision of the nucleus and its capsule, receives 

 confirmation*. But, under any circumstances, it is now manifest 

 that the sarcoblasts are true reproductive bodies, inasmuch as, 

 although I have not hitherto detected the passage of a sarco- 

 blast into a young Amoeba whilst yet within the Amoeba-cyst 

 above referred to, or within the frustule of the diatom (where 

 the sarcoblasts also occur under certain conditions to be detailed 

 immediately), I have traced the development of the young 

 Amoeba from bodies identical with them in appearance, and 

 occurring in a free state in the same medium and at the same 

 time. 



But to return to the history of the sarcoblasts whilst yet 

 within the Amoeba-cyst. When fairly formed, only a few 

 isolated granules are to be seen associated with them — the 

 endochrome of the diatom having become shrivelled and 

 discoloured, and nothing remaining to indicate the true origin 

 or office of the capsule. 



The most remarkable feature, however, has yet to be noticed. 

 The Amoeba occasionally seems to obtain an entrance into the 

 interior of the diatom-frustule, either during or after the ap- 

 propriation of its contents — but probably after, for reasons Mhich 

 will presently appear. As already stated, sarcoblasts are occa- 

 sionally to be met with within the frustular cavity. When this 

 happens, ingress has not been effected through any normal 

 apertures that exist in the structure, but through the partial de- 

 hiscence of the two valves at one extremity; whilst the de- 

 hiscence is, in all probability, connected with the presence of the 

 Amoeba to this extent only, that on the protoplasmic substance 

 being abstracted which serves as a support for the valves and 

 connecting zones, these fall asunder, and an opening is thus 

 established (PI. VIII. fig. 15). 



The greatest number of sarcoblasts seen by me within an 

 Amoeba-cyst was eight ; but generally it did not exceed half that 



* It is possible that the granules entering into the formation of the 

 nucleus, and which are undistinguishable, when isolated, from those of the 

 sarcoblasts, under any circumstances may have become diffused through the 

 endosarc generally. Hence my view as to the mode of formation of the 

 sarcoblasts and their non-investiture by a capsule receives corroboration. 



