8 BOTANICAL GAZETTE [JULY 
the sporangial filament that immediately surrounds it; while the 
non-stainable part, as in the case of the zones, is transformed into 
a permanent wall. The terminal spore thus ends in a cup-like 
depression (jig. 38, lower end), by which it is at once distinguished 
from the two other spores which compose the spore-chain at 
maturity. 
It is thus apparent, in these two instances at least, that the 
process of spore formation is distinctly different from that which 
has been described in Syncephalastrum, from the fact that the 
contents of the sporangial filament is converted into spores, not 
through its simultaneous separation into successive masses, but 
as the result of a more or less gradual intrusion of ‘‘intermediary 
zones” which develop from the periphery inward till the pro- 
toplasmic content is cut into segments. In the species last 
described it is evident that the intermediary zones consist of two 
parts ; one of which is, or at least becomes, a permanent struc- 
ture which, though formed earlier than and independently of the 
spore wall proper, is ultimately closely united with it; while the 
other constitutes an intermediate portion ultimately converted 
into an oily substance, although at first it seems to be protoplas- 
mic, and corresponding to the plane of separation between adja- 
cent spores, their function in this process being evident. 
A similar series of changes may be made out with sufficient 
distinctness in S. Wynne@ described below; but although in some 
of the common species, like S. nodosa and S. cordata, it is possible 
to observe the progressive constriction of the contents of the 
sporangial filament into portions corresponding to the spores, the 
extreme narrowness of the intermediary zones in these species 
renders it almost impossible to follow out the process in detail, 
yet it may be fairly assumed that these details are not essentially 
different from those above described. 
In the species subsequently described as S. tenuis a somewhat 
scanty supply of mounted material only has been available for 
study in this connection, so that it has been impossible to deter- 
mine the character of its intermediary zones. It will be noticed, 
however, that the species is peculiar in one respect, in that the 
