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of the organization or structure of the rhizopod, goes even 
further, and is. even more strongly evinced. I have men- 
tioned that from a definite region, from which the outer coat 
appears to be wanting, emanate the ordinary pseudopodia, 
and that these can be withdrawn. Now examples are, how- 
ever, by no means rare, which watched for a long time and 
made to roll over, show no tendency to project pseudopodia 
nor any difference in the outer coat, which, viewed from 
various points, seems like an everywhere present sharply- 
defined rim, and, as the case may be, more or less pilose or 
hairy in appearance. I am, then, half inclined to suppose 
that even the parts of the outer coat which permitted the exit 
of the tuft of pseudopodia, or perhaps too allowed a prominent 
portion of the body-mass to project, can again become closed 
up, and the creature become completely invested at all 
points by this remarkable outer coat. Nor is such a her- 
metically closed in example torpid or “ encysted;’ it is 
perhaps quietly all the time assuming various contours, from 
a nearly globular to various bluntly angular forms; and 
even perhaps, as I have seen more than once, such an 
example may send forth unexpectedly, mostly at one or even 
two of the corners produced, a blunt pseudopodium through 
the wall. On the other hand, that a certain amount of what 
may point to the reality of a kind of differentiation into 
*‘ anterior ” and “ posterior” ends, may be said to be evinced 
not only by the frequency with which examples present 
themselves with the pseudopodia confined to one space only, 
but also by the fact, so far as it goes, that the “nucleus” 
appears usually to occupy a position at the side remote from 
that of the pseudopodial region, thus perhaps offering a cer- 
tain amount of analogy to several other forms of Rhizopoda, 
where anterior and posterior extremities are distinctly pro- 
nounced, and in which the “ nucleus ” always occurs behind. 
In the progress of our ideal building up of the form now 
under consideration, and in our gradual advance from within 
outwards, I purposely left in abeyance a characteristic evinced 
by the sarcode body-mass, one however which appertains to 
it in common with a great many other Rhizopoda, and to 
that body-mass itself I must for a moment revert. I refer to 
the formation of vacuoles therein. I left the allusion to this 
in abeyance, because the appearances accompanying its dis- 
play are curious in relation to the presence of the remark- 
able outer coat, which I proceeded therefore to describe 
first. 
Although, however, the formation of pulsating and non- 
pulsating vacuoles is a phenomenon so frequent in various 
