ARCHER—ON RHIZOPODA. 241 
dopodia should at all raise a doubt that we had a true Rhizopod before 
us, and not actually some vegetable production which the cells might 
eall to mind, the encompassing of so unusual and so comparatively un- 
manageable a subject of attack asa portion of a fibre of wool by a fine 
specimen of this noteworthy form, which I witnessed, would settle the 
point. A fibre of wool happened to be in the dip made from the 
gathering and presented itself upon the slide, and in close contiguity 
to it a large specimen of this new form, copiously filled with the central 
cells, and abundantly spreading forth its pseudopodia, not quite so 
much so, however, asin other specimens [had seen. By degrees, I think 
more by accident due to some external force, probably exerted by 
myself in slightly modifying the position of the covering glass, the 
Rhizopod and the woolcame into contact. I waited with curiosity to 
see whatit might do. The Rhizopod first spread itself down along the 
wool, and the central cells, in place of forming a rounded cluster as at 
first, became distributed in a crowded drawn-out series. Meantime the 
pseudopodia by degrees began to disappear along the sides, but to pre- 
sent themselves in increased force upwards and downwards along the 
wool, as it were seemingly mooring the Rhizopod to the wool. Pre- 
sently these reached quite up to one end of the wool, and the sarcode 
mass seemed to follow, until finally the wool was wholly covered by it 
at one end, the mooring pseudopodia disappearing at each end, whilst 
the general sarcode mass seemed to become stretched so as to envelope the 
wool. As the animal became thus extended along the fibre of wool 
which it had thus to a great extent incepted, it, of course, became 
somewhat more tense, and hence the wool took a curved or bowed 
figure, and the sarcode mass became stretched straight across the con- 
cave side, but thinly disposed along the convex, which is the state I 
have tried to represent in the accompanying drawing (fig. 2). During 
this elongation of the sarcode mass the central cells, now disposed in a 
nearly single stratum at the upper and lower ends, or even isolated, 
‘seemed in other places to have become extruded beyond the outline of 
the sarcode body. But, though seemingly thus expelled, they did not 
separate; and I conclude they must have been removed beyond a 
certain region only of the sarcode body, that which presented the out- 
line whose tenacity caused the bending of the wool, and that there 
must have been an outer stratum of a very hyaline character and great 
tenuity which was able to retain the so partially extruded central cells 
from becoming wholly cast off. However inert, then, this organism 
when first detected under the microscope, and however great the resem- 
blance to some vegetable form which it might present under a low 
power which might not reveal the existence of the pseudopodia—nay, 
hardly even render it very discernible, without some practice, from 
some of the Protococcaceous forms which presented themselves in 
most of the gatherings in which this form was found—yet such an ob- 
servation as that detailed demonstrates that this is really a Rhizopod ; 
and the amount of energy displayed after coming into contact with the 
foreign body, as compared with its ordinary comparatively inert state, 
