ARCHER —ON RHIZOPODA. YM | 
surrounded by a common investment of a more cloudy, very pale, or 
slightly buff-coloured sarcode matter, and of a more changeable cha- 
racter. Occasionally one meets, but rarely, however, examples with 
but a single central globe, and, indeed, those with two or three only 
are uncommon: some six or eight are more frequent, and such ex- 
amples are quite large enough to be visible to the naked eye. One meets 
some sometimes of very considerable size with comparatively numerous 
globes. Proceeding outwards, we find that, immersed in this general 
sarcode envelope, are contained an immense number of very slender, 
hyaline, acicular, siliceous spicula, acute at each end. ‘These are nu- 
merous beyond all computation, and so densely crowded that they do 
not individually occupy any definite direction, but are found tossed 
about, as it were, reminding one of a loosely tumbled-up heap of pins 
(without heads, however, and pointed at each end). These never en- 
eroach into the substance of the inner globes. Emanating from amongst 
these spicula, lastly, proceed in every direction very numerous, closely-set 
- pseudopodia, which are exceedingly long and quite straight, of immea- 
surable tenuity, quite hyaline, and not seemingly carrying granules. 
The opacity of the outer stratum, with its abundantly crowded spicula, 
along with the great fineness of the pseudopodia, together prevent our 
making out whether the latter take their origin from the inner globes 
or from the outer stratum. I imagine, however, so far as I can see, as 
well as from analogy of other forms hereafter to be drawn attention to, 
that they proceed from the contained inner globes directly through the 
outer stratum. 
I have said that the spicula do not assume any definite position, 
but this is hardly always correct; for, shortly after a specimen of this 
form is placed upon a slide for examination, and after it begins, as it 
were, to recover the shock of the transference, certain of the external 
spicula do begin to assume a more vertical or radial position, especially 
subjacent to certain of the pseudopodia. Along these they become 
-crowded and lie up against them, forming around each of such a some- 
what conical aggregation. They thus form a kind of involucrum (so 
to speak) to the pseudopodium which they invest, of an elongate- 
triangular outline, from the apex of which projects the pseudopodium 
afar into the water. Not all the pseudopodia become so notably sur- 
rounded by these clusters of spicula, but only a number, distributed at 
somewhat even distances, present this appearance, whilst the majority 
start off from the outer periphery of the Rhizopod, from amongst the 
general crowd of spicula, without becoming specially surrounded by a 
cluster of them. Such a description would seem to attribute to the spi- 
cula an independent power of change of location and of mode of arrange- 
ment; but, althoughin watching an example of this Rhizopodas itexpands 
and gradually assumes its characteristic appearance under the micro- 
scope, it would almost seem as if some out of the dense mass of spicula 
spontaneously underwent a certain amount of arrangement as described, 
this, however, must be of course attributed to the mobility of the sar- 
code matrix itself, forming the outer stratum in which they are im- 
