100 
Proceedings of the Royal Irish Academy, 
But, although I am disposed, at all events provisionally, to regard 
the first rhizopod I have in view, and attempt to repeat in Plate XIII., 
Fig. 11, asFIayiophrys sph(erica{C\^]). etLachm.), still, on comparing our 
form, after a prolonged examination and experiments with re-agents, with 
Claparede and Lachmann's diagnosis, I am at the first step met with a 
character which might seem possibly to exclude it from the genus 
Plagiophrys. I allude to the fact that those rhizopods, meant to be 
included here, are said by the authors to be comparable to ' ' Actino- 
phryens non cuirasses," and whose numerous pseudopodia originate 
in a tuft from a single portion of the surface of the body. But if those 
authors deny a test (they ordinarily use the word coque") to the 
(two) forms included in Plagiophrys, they attribute to Plagiophrys 
cylindrica (a form I have never encountered) a skin ('^peau"), whilst 
in respect to P. sphmrica they are silent in this regard ; but it is, I 
imagine, exceedingly probable that, so far as concerns this, the account 
given of each should coincide, and were most probably meant by the 
authors to be so understood. But, beyond the fact that the figures 
represent the forms as possessing a quite smooth surface and sharp 
outline, there is no evidence afforded of the so-called ^'skin." The 
question, then, becomes, what they meant exactly to convey by that 
term ; but presumably it must have been, not a separable integument 
enclosing the sarcode body (certainly not a test or coque"), but only 
a more dense and hardened, or rather toughened, exterior to the body, 
forming therewith a single inseparable whole, both being in complete 
organic union, and thus, only that it is less yielding, hardly, if at all, 
more than what has been attributed even to Amoeba itself by some 
observers, as Auerbach and others. And, in fact, I had myself several 
times met with the rhizopod I am still disposed provisionally to regard 
as Claparede and Lachmann's form alluded to, and that without per- 
ceiving any further differentiation into body and integument than that 
I should suppose those authors were inclined to attribute to it. 
Hence the experience, presently to be adverted to, gained from the 
preparations of both my forms under Beale's carmine fluid (Fig. 16), 
and under acetic acid (Fig. 12), does not appear to militate against the 
correctness of the identification of the first form here figured with 
Plag. sphmca, for in the living example this outer case, or covering, is 
always so closely applied to the body as to appear indeed no more than 
a smoothly bounded exterior, w'hich might seem possibly, to a certain 
extent, to be comparable to a ^' skin." 
But, although I cannot but suppose the identity of the form I 
sketch in Fig. 1 1 to be probable, as I have mentioned, I regard this de- 
termination as yet as but provisional for certain other reasons. 
The first is that my form shows a distinct ''nucleus," or body so 
called. N^ow, in this regard Claparede and Lachmann are silent con- 
cerning their Plag, sphcerica, but they distinctly state they were un- 
able to detect this in their Plag. cylindrica. Still, as this is only 
evidence of a negative character, it does not disprove the identity ; for, 
owing to the density of the contents, the nucleus may have been pre- 
