90 
the interior, which show the same movement as the granules 
in the pseudopodia of the Rhizopoda. The fibres become 
finer and finer towards the surface of the animal, until at 
last they form a meshwork under the outside skin, which is 
fastened to the same by a finely granulated, cellular 
layer.” For every one who wishes to read I thought this 
clear enough. The difference between my view and that of 
Dr. Donitz is that the substance between the sarcode skeleton 
(, geriist ), which I have taken to be organic, he has considered 
to be salt water. If I have used a term (in the shortly 
framed diagnosis, which was meant merely to sharply charac- 
terise the one group from the other) which suggested a cellu- 
lar multiplicity, I may, perhaps, be to blame ; it cannot be 
imputed to me, however, in direct contradiction to my un- 
mentioned full description, that I imagined for one instant 
there could be a parallel drawn between the substance of the 
Noctiluca and the connective substance of the vertebrate 
animals. 
Dr. Donitz goes on to say, in page 146, “These cells ['the 
obviously cellular layer’ of the outer skin, as mentioned above 
by me] are nothing more than the meshes themselves, which, 
bjr a superficial examination, could betaken for an epithelial- 
like layer. To suppose that there are cells here, one would 
be obliged before all things to prove the presence of a nucleus, 
which would be exceedingly difficult in this case.” 
Dr. Donitz, who has not seen the nuclei, may excuse him- 
self on account of the difficulty. But to attribute to me, 
who have seen the nuclei, a merely superficial examination, 
is certainly extraordinary, the more so that he has not given 
himself the trouble to see if others besides myself have 
observed the same. But now, in the twelfth number of the 
‘ Zeitschrift v. Wissenschaft. Zoologie/ page 564, there is a 
paper by W. Engelmann, on the “ Cellular Multiplicity of 
the Noctilucte,” of which Dr. Donitz should have been aware 
if he thought necessary to make remarks on this animal. 
There the nuclei are mentioned, figured, and measured. 
Seeing that Engelmann and I have come quite independently 
to the same view of the structure of the Noctiluca, I think 
that our almost simultaneously published views may be con- 
sidered as confirming one the other. 
On which side is the superficiality, if not of the exami- 
nation, at least of the critic, I leave the reader to decide. — 
Leipzig, 15th September. 
On Naked Fresli-water Radiolaria. By Dr. Gustav 
Woldemar Focke, of Bremen. Zeitschrift fur Wissenschaft - 
liche Zoologie, heft 3, September, 1868. "We give this paper 
elsewhere in full. 
