ARCHER, ON STEPHANOSPH ERA PLUVIALIS. 123 
one of these isolated motile bodies disassociated from a 
Gonium-tablet from an isolated motile body set free from an 
old Stephanosphera globe, both of which, after the emegr- 
ence of the latter, moved freely about in company ; nor, apart 
from a knowledge of their origin, could either be distinguished, 
I think, from so many examples of Chlamydomonas had they 
been present. 
But from this I do not mean to argue more than a puzzling 
resemblance between the two. A. single Gonium in the 
original material would have sufficed to give origin to the 
multitudes which afterwards made themselves apparent, con- 
spicuous even to the naked eye, by their mass. I should be 
disposed to hold that here, as elsew here, resemblance may by 
no means necessarily demonstrate identity ; and although 
these isolated motile bodies, thus proceeding from Gonium 
and Stephanospheera respectively, were so much alike as to 
be indistinguishable to the eye, for the present I doubt not 
there must have been between them some more subtle dis- 
tinction, and that in the progress of development in their 
natural conditions they would each have gone into their 
respective mature forms (and this notwithstanding what 1 
have afterwards to advance), although Cohn did not see (nor 
have I noticed) the isolated cells of Gonium, but only those 
still undisturbedly in situ, become segmented, and directly 
form a new young Gonium- tablet ; whilst, on the other hand, 
as has been stated, it can be demonstrated by direct observa- 
tion that in Stephanosphiera the single Chlamydomonas-like 
primordial cell eventually produces a new Stephanospheera- 
globe. Cohn neither in his first nor in his and Wichura’s 
subsequent memoir on Stephanosphera makes any allusion 
to any development of Gonium making its appearance in the 
material which formed the subject of his earlier observations 
on the former organism; but I find that he incidentally 
mentions, in his memoir on Gonium,* that on one occasion, 
at least, a copious development of this latter organism took 
place in a vessel in which he had been cultivating Stephano- 
sphera; and that in so great quantities, that the water 
resembled a green mucus, and in each drop thousands 
abounded. This is, then, at least a possibly noteworthy 
coincidence, and the circumstance, quantum valeat, is perhaps 
deserving of this cursory record. 
A third developmental change of the primordial cells of 
Stephanospheera, connected doubtless in some way with pro- 
pagation, is that which results in the formation of “ micro- 
gonidia.’” Their development is at first like that of the 
* Op. cits. p69. 
