ARCHER -——ON RHIZOPODA. 243 
reproductive cells. Whilst there is, no doubt, a resemblance, the mode 
of branching form assumed by the pseudopodia in each is sufficiently 
characteristically different, at least to my eyes, and as, I think, an in- 
spection of both Schultze’s figure and that which I have made of my 
Cystophrys Haeckeliana will sufficiently indicate. Hardly anything 
can be prettier than the gradual expansion, under one’s eye, of an ex- 
ample of the form referrible to Schultze’s 4. porrecta, presenting itself 
first as a little shapeless sarcode lump, and then extending into a wide- 
spreading, reticulose, densely ramtfying combination of several little 
trees, under a higher power quite filling the field of view. 
From the naked forms represented by the more familiar Actino- 
phrys, the subarborescent character of the pseudopodia would alone 
readily distinguish our Rhizopod, even though it did not possess the 
central cells. In our new form there does not appear any body or 
structure equivalent to the so-called ‘‘ nucleus,”’ as that term is applied 
to the peculiar body in Ameba, Difflugia, and some other forms to be 
described hereafter in a future part of this paper. The absence ofa 
test shuts out this form from a few whose pseudopodia may otherwise 
resemble it. There is, moreover, in our form no “ contractile vesicle.”’ 
As regards, then, other Rhizopods destitute ofa test, itis distinguished 
from Actinophrys by the subarborescent character (so to call it) of the 
pseudopodia and by the central cells. From Raphidiophrys, whose 
pseudopodia are still more delicately slender than those of Actinophrys, 
and do not fuse at all, it is distinguished by the absence of the spicula 
and the presence of the central cells—in fact, the possession of the 
central cells shuts our form out from every other freshwater genus, not 
to speak of the other wide distinctions drawn attention to. 
It might suggest itself, then, as I have alluded to, that these very 
central cells might point to an affinity of the marine forms comprised 
under Haeckel’s “ Radiolaria,” that is, if the cells in our form were 
thought to be at all the representatives of the so-called ‘‘ yellow cells’ 
which pervade that great group, with the exception of Haeckel’s family 
therein—the ‘“* Acanthometrida.”? As we have seen, these central cells 
seem, like the ‘‘ yellow cells” of the great majority of the Radiolaria, 
true ‘‘ cells,’’* in the strictest sense or application of the word ; that is 
to say, they possess a nucleus, nucleolus, contents, and a wall, and so 
do the ‘‘ yellow cells,” as described by Haeckel; and, what is equally 
important, both agree in the mode of self-division of the contents. In 
short, the central cells in the Rhizopod now brought to notice seem to be, 
if the expression be allowable, to all intents and purposes homologous 
with Haeckel’s ‘‘ yellow cells,” except that they are not of a yellow 
colour; at least, not yellow, contents and all, as depicted by Haeckel, 
yet still the cell wall has a slight greenish-yellow hue, whilst, how- 
ever, the contents have that greyish-blue tint very like that of the 
so-called ‘“‘nucleus” in Ameeba, &c. But, even admitting that the 
* Haeckel, op. cit., p. 84. 
VOL. V. 2K 
