39 
New Marine Fungi on Pelvetia. 
following the first appearance of the disease, is doubtless due to 
the quick dispersal and immediate germination of these small bodies. 
The ascigerous fruits appear slightly later on the same patches. 
They originate in masses of mycelium in the cortex, which increase 
and give rise to asci before distinct perithecial walls are formed. 
The place of the latter is taken largely by the superincumbent 
layers of the host which become blackened to form a kind of false 
clypeus. This becomes raised to form a hemispherical dome pierced 
later by the irregular ostiole. A thin perithecial wall is formed 
under this but it does not extend along the flattened or occasionally 
curved base, bounded only by the mass of hyphae from which the 
reproductive bodies spring. The poor development of the peridium 
may be accounted for by the protection given by the blackened 
overlying tissue, represented in Pig. 2, 3. As this becomes thinner 
the membranous wall is formed. 
This method of perithecium formation has been noted in other 
fungi examined by the writer in algae. When placed in the muci¬ 
laginous bodies of the latter there is less need for protective walls. 
The perithecia are large and readily visible to the naked eye. 
They contain numerous long cylindrical asci with very slightly 
thickened tips and mixed with longer septate branched and 
unbranched paraphyses as in Fig. 2, 5. The hyaline spores are 
uniseptate with a distinct constriction marking off the upper 
broader cell from the lower narrower one. When mature they 
contain several oil globules. 
In the broken-dow'n tissue on the surface of the blackened 
patch numerous hyaline elliptical conidia are found. As the tips 
of hyphae penetrate into this layer it may be that these are cut off 
from them. They are seen in Fig. 2, 3. 
This species is placed in the genus Stigniatea with some 
reservation. The spore characters, asci, paraphyses and some other 
features combine to ally it with this genus. It is, however, a moot 
question whether the origin of the perithecium and its distinctive 
character do not justify its being placed in a separate and new 
genus. This can be settled definitely only when the other algal 
fungi are examined and the whole matter of perithecium formation 
studied with regard to the new conditions involved in this type of 
host. 
PHARCIDIA PELVETIA NOV. SP. (Fig. 3, 1—3). 
Mycelium thick, brown, and parasitic, frequently forming a 
superficial web in addition. Perithecia minute, 45-55^, spherical 
