260 
PEOCEEDINGS OF SOCIETIES. 
ing occurrence of the process of division is the separation of the endo¬ 
chrome, which becomes, as it were, cut through-and-through abruptly 
into two exactly hemispherical masses, separated by a straight, sharp, 
smooth line ; a slight elongation of the cell next occurs, which goes on, 
pari passu , with a constriction of the cell-wall immediately over the 
equatorial line of separation of the endochrome, at which stage the divid¬ 
ing cell becomes of a figure of 8 form. The first I met with undergoing 
this process I thought might be in a state of partial conjugation; but by 
a little further observation it became evident that this was a process of 
division. When a specimen has become so far divided, it has assumed 
a quasi-Desmidian appearance, as it might possibly be taken for a large 
Cosmarium; bat the separated halves of the endochrome of the original 
spherical cell soon lose their exactly hemispherical form, grow larger, 
ar.d become rounded off, having secreted a special cell-membrane, and 
eventually, as two distinct individual cells, similar to the parent, emerge 
from its loose old cell-wall by rupturing it (Pig. 17). This escape of 
the newly formed spheres seems to occur sometimes before the constric¬ 
tion of the old cell becomes entirely cut off. At other times this con¬ 
striction is perfected, and single cells are thus frequently met with, the 
old cell-wall surrounding the newly formed cell like a loose tunic. 
Supposing that M. Hofmeister’s plant follows the mode described, 
might not the bursting (at the annular groove) of the constricted old 
cell, before the deepening constriction becomes entirely cut off, account, 
at least in some measure, for the openings or orifices described by him as 
met with in the empty coat ? I have myself in our plant often found the 
cast-off coats, which are met with usually collapsed or wrinkled, and 
sometimes with an orifice like what might be supposed to occur under the 
conditions indicated. However, M. Hofmeister relates his having occa¬ 
sionally noticed as many as six coats inside each other. In the plant met 
with by me I have not seen more than one inside another. I am not able 
to state that in our plant the cell-contents, without division, first con¬ 
tracting, secrete a new cell-membrane still within the original coat,— 
such a process being, I imagine, the only way to account for the fact of 
several loose coats concentrically surrounding the same cell. Thus, 
while it appears as by no means decided that M. Hofmeister’s plant and 
that alluded to as met with here, are identical, yet I think it will be at 
least evident that they resemble each other very much, and are closely 
allied. 
M. Hofmeister has already compared his plant to a Desmidian. At 
first sight ours has some resemblance to Cosmarium Ralfsii; but, being 
a perfect sphere, it, of course, wants the constriction and elliptic ends of 
that species. I hardly think, in our plant, that there is a central suture, 
though the cast-off coats have a tendency to split into two hemispherical 
portions: they often display, after collapse, a flattened or depressed cir¬ 
cular portion (when viewed sideways, almost as if a small segment had 
been abruptly cut off the sphere), possibly representing the somewhat 
flattened surface of contact with the companion cell, just after the 
complete shutting off of the two cells 6r entire formation of the double 
