506 HoweE: PHYCOLOGICAL STUDIES 
are anything other than normal parts of the Avrainvillea itself ; they 
certainly contain chlorophy! and starch and the chloroplasts appear 
to be of the same character as those of the ordinary filaments of 
the thallus. Indeed, the supposed sporangia occur in too great 
profusion, even though on a single plant, and they are too regular — 
jn form and position, we believe, to be anything else than normal. 
The sporangia are always terminal on branches, which, except 
for the presence of the sporangium, are but slightly different from 
the ordinary vegetative filaments of the flabellum, being, however, 
less moniliform or torulose, and often more slender than the fila- 
ment from which they spring. These sporangiophores result from 
the ordinary forking of the filaments and they are commonly 
homologous with a vegetative branch which would undergo two 
or three more dichotomies (FIGURE I 5). Some which can be traced | 
back to the deeper-lying filaments are falsely lateral in origin. The 
form of the sporangia has been alluded to above, but the figures — 
published herewith give a more accurate idea of their character. — 
They vary from 0.35 to 0.83 mm. in length and from 0.20 to 
0.35 mm. in width. Sometimes, as shown in FIGURES 22 to 24, the 
base of the sporangium, underneath the spores, is occupied by a 
brownish mass of slime or mucilage, forming a more or less com- | 
plete basal septum. The plug, however, is perhaps more Com 
monly near the base of the sporangiophore, as shown in FIGURE 15. 
Occasionally, as in FIGURE 13, the stoppage is near the middle of 
the sporangiophore. Often, two such plugs may be found, one at — 
the base of the sporangium and the other at the base of the spor 
angiophore. The brown callose-mucilage evidently furnishes the 
material for healing the wound caused by the withering away © 
the empty sporangium. Numerous brown, rounded, thick-walled, 
stump-like processes, like that shown in FIGURE 20, may be found, 
indicating the position of former sporangiophores. It rarely hap- 
pens that practically the whole protoplast of the sporangium - 
consumed in the formation of a single spore, but the usual number — 
is three, four, or five, as stated above, though occasionally as many 
as SIX, seven, or eight are formed. The spores are most commonly 
long-ovoid or pyriform and as they lie in the sporangium the 
broader end is usually upward, They are densely crowded with 
chloroplasts and starch-grains but as they mature the amount of 
a aaa rat 
