334 On the Formation of the Spore in a species of Vesiculifera. 
portunity of satisfying myself as to the real character of the pro- 
cess, and I can give the following as the result, not only of my 
own observations, but fortified by the opinion of Mr. Berkeley as 
to their correctness, to whom I submitted specimens for exami- 
nation. 
The species in question may possibly be the V. lacustris of 
Mr. Hassall, with which species it would appear to agree in size, 
but I cannot determime with any certainty from his figure and 
description. The plant occurs in ponds on a common near Bristol, 
and is of a pleasant pale apple-green colour. The cells are usually 
from five to seven times as long as broad, and are lined with but 
a small quantity of endochrome which is ‘disposed i in a reticulate 
manner. Some of the cells, however, may be observed to be 
slightly inflated, and to contain a larger amount of endochrome 
than the rest: in each of these mflated cells a spore is subse- 
quently formed, and in the following way :—The endochrome, 
-after attaining a certain degree of density from an increase in its 
development, not from any derived from a contiguous cell, moves 
towards one end of its cell ; it (the endochrome) shortly becomes 
divided into two very unequal portions, the larger and terminal 
one of which becomes converted into the spore, and the smaller 
portion is found to be separated from this bya single septum. A 
process has, in reality, taken place analogous to the fissiparous 
division of the cell of Zygnema; two cells have been formed 
within the original one, but in the Vesiculifera one of these new 
cells is the spore. 
This is a fact of considerable physiological importance, and I 
shall have more to say on this subject in a future communica- 
tion. 
P.S. March 25, 1846.—Since writing the foregoing I have re- 
ceived a letter from Mr. E. J enner, who is well-acquainted with 
the species intended by Mr. Hassall’s descriptions, informing me 
that the Vesiculifera mentioned above is the V. concatenata of 
that gentleman’s work. 
I have today examined very carefully specimens of Vesiculifera 
equalis, Hassall, and find that the process of the formation of the 
spore is similar to what I have stated to take place in V. conca- 
tenata. In the V. equalis, however, I have been able to trace 
the mode of development of the two or three contiguous spores, 
which are sometimes to be seen in the filaments of this species : 
the first spore is formed in the way I have previously mentioned, 
and arrives at considerable maturity before there is any appear- 
ance of one, contiguous to it, being produced ; but it may then be 
seen that the vinntier portion of endochrome, which had been 
separated just previously to the first spore being formed, and 
