Archeh — On Freshwater' Rhizopoda. 
73 
conical, or slender and tapering, colourless or pale bluish processes or 
pseudopodia. (Figs. 1, 2.) These, for a reason to be immediately 
explained, mostly emanate from a restricted region of the body-mass, 
and are very fitful, never kept extended lo2ig at a time, nor that often ; 
but further, a few still more fitful and less elongate pseudopodia can 
sometimes be projected from other parts. (Fig. 2.) The locomotive 
power of this form appears very restricted. If then our form 
presented no additional character, it would still be but an Amoeba-form, 
or one, owing to the pseudopodia being of a one-sided tendency, 
perhaps, approaching Bailey's genus, Pamphagus. 
But our form is more still than this ; and, to continue our progres- 
sive examination from the amoeba-like form we have reached, we find 
this so-described body-mass is enclosed in a kind of mantle or coat, 
closely investing it ; and this is of a highly curious and remarkable 
character, which I shall now endeavour to describe. 
When a living example of this rhizopod is first placed under 
examination, even though its normally orbicular figure be more or less 
distorted, this outer coat appears not only to surround the body 
closely at every part, but to form a rim-like exterior in complete 
union with it ; that is, as it were, but a more dense and diff'erentiated, 
but sharply-marked off, outer boundary to the body-mass, whose 
changes of figure it necessarily follows. On further examination, it is 
seen to possess a number of vertically-posed and parallel lines in 
its substance, and reaching through its thickness, giving a striate ap- 
pearance to this rim-like investment. This appearance is often very 
striking ; but specimens occur in which it is, more or less, difiicult to 
be made out ; yet a little trouble, and it can be seen in all. Further, 
on the outer surface of this coat, there mostly occurs a dense clothing 
of more or less elongate colourless, very slender, hair-like processes, of 
very variable degree of development. Sometimes these attain a length 
at least equal to one-third (Fig. 1), perhaps even sometimes approach- 
ing one-half the diameter of the body of the rhizopod, whilst, in other 
specimens, these hair-like processes appear much shorter (Figs. 2, 4), 
giving a merely pilose appearance to the surface, or, so short are 
they, as even to impart a merely roughened or granular aspect to 
the surface or periphery of the coat (Fig. 5) ; and again, they ap- 
pear in certain other examples as all but obsolete (Fig. 3). An 
empty coat presents a dotted appearance all over (Fig. 4). These 
hair-like processes, especially when well-developed, appear, on first 
examination not unlike pseudopodia, and one might be inclined to 
suppose we had before us a Heliozoan form (resembling a form, 
perhaps, referrible to Greeff's genus, Astrodisculus^'), rather than one of 
Amoeban afiinity ; but that, as is seen, would be a wholly incorrect 
interpretation of the characteristics of our form. 
I have said this outer coat appears to form not only a complete 
* Greeff, *'Ueber die Radiolarien des siissen Wassers," in Scliultzes "Arohiv 
fiir Mikroskopischen Anatomie ;" Bd. v. p. 496. 
K. I. A. PHOC VOL. I,, SEE. II., SCIENCE. L 
