104 Rhodora [APRIL 
branchlet, which has been cut off by a septum from the oogonium 
which later forms below it. In some instances the antheridia may 
normally arise in an intercalary fashion like the oogonia, in others, 
again, both conditions may occur (fig. 10). In a majority of cases 
typical antheridia may be formed apart from oogonia, while in two 
this diclinous habit seems to be invariable. In several species, also, 
these solitary antheridia are associated with larger clavate organs. 
resembling the sporangia of some Saprolegneae, and between the 
two forms there usually appear a variety of intermediate conditions. 
These larger clavate organs have been assumed to be zoosporangia 
containing uniciliate zoospores, but although Lagerheim describes. 
and figures the germination of one of the latter which we must assume 
he followed continuously from its exit from the sporangium to its 
germination, the possibilities of error in such observations are so 
numerous that it cannot be regarded as finally settled that these 
structures are not all more or less modified antheridia. 
Whether these structures are in reality sporangia or are merely 
more luxuriantly developed antheridia is, however, a matter of little 
importance in connection with the main point which I desire to 
emphasize; namely that the species of Monoblepharis are character- 
ized by the production of zoosporangia which are the morphological 
equivalents of the oogonia, and in which biciliate zoospores are pro- 
duced. This is not only true of the two forms which Lagerheim has 
set apart under Diblepharis; but of all the other species including his 
own M. brachyandra, a variable species which appears to occur not 
infrequently in the vicinity of Cambridge. These sporangia (figs. 8, 
9 and 11) show the variations of form characteristic of the oogonia 
of the species in which they occur, and may be distinguished, after 
the zoospores (fig. 12) have escaped, by the residual globule or 
globules of oil which are conspicuous in them before and for some 
time after the spore discharge. 
Although theses porangia are less commonly produced in some 
species than in others, and their abundance varies in different speci- 
mens, I have seldom examined material in which they did not occur ; 
and in M. polymorpha especially, they may almost wholly replace the 
oogonia. It seems very improbable, in view of these facts, that such 
organs are not equally characteristic in European material, and it is 
necessary to assume that they have been overlooked. That they are 
not accidental or unusual productions, is beyond question ; and it is 
