RECENT MEMOIRS ON FRESHWATER RHIZOPODA. 353 



the application of Beale's fluid caused the contraction, or a 

 kind of coagulation as it were, of this outer region and the 

 disappearance of the fimbriated margin, the processes com- 

 posing it seemingly contracting into a few mere short, 

 rounded, thickened, stumpy-looking elevations. Now the 

 true spines of several (two or three) examples of Acantho- 

 cystis Pertyana, which luckily happened to be on the same 

 slide, were not altered at all — in fact it would have been 

 highly surprising if they had been. But further, in the living 

 state it appears to be of, so to say, a soft nature, more or less 

 yielding to certain (restricted), doubtless accidental, changes 

 of figure of the whole organism. In the form which I called 

 Heterophrys Fockil,^ I may admit, as being destitute of the 

 fimbriated margin, possibly not wholly correctly relegated to 

 one and the same genus, this outer region is still more plastic 

 and changeable in contour and even in position. 



It has always rather struck me that this cloudy layer of 

 granular, and striate (in H. Fockii, of " streaky ") appear- 

 ance, must be considered as analogous to the certainly less 

 soHd and less pronounced — might one say more ethereal- 

 looking — envelope sometimes noticeable, more or less in- 

 volving the spines, and the lower parts of the pseudopodia 

 of Acanthocysiis turfacea, as referred to hereafter, as well as 

 to the same region in the genus Raphidiophrys. 



But to go a step further and take into consideration the in- 

 teresting form referred to this genus, but seemingly really dis- 

 tinct owing to its not being homaxial and possessing branching 

 pseudopodia and numerous nuclei, called Heterophrys varians 

 by Prof. Eilhard Schulze," we have a form in which this outer 

 envelope, which, however, is clear within and granular, but not 

 fimbriate, at the periphery, is for a time normally absent, 

 only ultimately making its appearance. This Schulze (pos- 

 sibly not inaptly) compares to the gelatinous investment 

 exuded by many alga?, rather than to a " skeleton." I have 

 no doubt that this form has occurred to myself, but I had 

 not sufficient material at command to subject it to a study. 

 There can be no doubt, however, but that it is the same as 

 that recorded by Greeff, under the new name of Heliophrys 

 variabilis,^ a resume of whose description will be given 

 hereafter. 



As regards the minute peripheral clear space around the 

 central body and the outer envelope in question, we are I 



' ' Quart. Jourii. Micros. Sci.,' n.s., vol. ix, p. 267. ■ 

 - Schulze, " llliizopodeustudieu," Schultzc's 'Arcbiv f. Mikr. Anat.,' 

 Bd. X, p. 386. 



3 Greeff, iu ' Schultzc's Arcliiv fiir Mikrosk. Anat.,' Bd. xi, p. 28. 



