Archer — On Freshwater Rhizopoda. 
81 
The central body of all, the so-called nucleus, " is, of course, quite 
homologous with the similar so-called body in Amoeba, in Difflugia, 
in Diaphoropodon, in Pleurophrys, in Eugiypha, in Cyphoderia, in 
Plagiophrys, in Pamphagus, &c., &c. The tapering hyaline non- 
coalescing pseudopodia have the essential characters of an Amoeban" 
rhizopod, wLilst the contractile vacuoles, if not exactly alike, much 
resemble them, but still more those of an Actinophryan." The pale 
shiny, mostly elliptic, granules are again found in Amoeba, and related 
Ehizopoda, and are probably equivalent to the sarcoblasts" (Wal- 
lich) of Amoeba; whilst the chlorophyll-granules of the present are 
again seen in some Difflugians as well as various other E,hizopoda, tem- 
porarily in some, or possibly constantly in others. The special and very 
remarkable and very puzzling character of the investing mantle or 
coat would x)lace such a form as ours out of all the older Amoeban" 
genera. This coat is at once yielding and plastic, elastic and tough, 
seemingly capable of being bored through and effacing the aperture — 
possibly, however, minutely perforate — and is clothed with processes of 
variable length, these separable under certain re-agents, as if in a 
measure articulated, resisting some re-agents, at once disappearing under 
the action of others. This is, therefore, not a test comparable to that 
of Difflugia, or Eugtypha, or Plagiophrys, &c. What, too, may be 
assumed to be the nature or liomology of the outer hyaline investment, 
depicted in Eig. 3, and described above ? Does its existence at all 
point to the presence of actual canals in the coat indicated by the ver- 
tical or radial striae, and is this an emanation poured out through such 
canals, comparable to the ectosarc of an Amoeba, or is it rather to be 
regarded as chitonosarc" (Wallich)"^' ? If, indeed, the mantle or coat 
described be not, as I have throughout regarded it, a truly external 
investment, but a wall placed between the inner body-mass and an 
always existent, though, on account of its very pellucid and subtle 
nature, seldom visible, outer region of the total rhizopod, then the exist- 
ence of little actual canals need not necessarily be assumed. Perhaps, 
even such an assumption may not, after all, be quite unfounded, for 
though this lialo is rarely evident, yet a kind of bright outline 
often presents itself immediately external to the striate coat, which, 
however, I have rather been inclined to ascribe to an optical effect 
than +0 the visible expression of the existence of an actual outer 
investing sarcodic stratum, however delicate, or of however slight 
depth. Might the fine vertical lines seen in the substance of this subtle 
covering actually indicate the very moment of formation or deposition 
of the hair-like processes? The weak action of the sulphuric acid 
seems to have the effect of dislocating (some, at least, of) these as if 
they were, in a measure, articulated to the coat. * 
While, then, much that is puzzling and enigmatical remains un- 
solved, enough is evidenced to show the immediate ^'Amoeban" affinity 
* Wanich : " On the Polycystina," in " Quart. Journ. Micr. Science," vol. v., N.S., 
page 71. 
R. I. A. PROO. — VOL. I., SEE. 11., SCIKNCK. M 
