Coker: Two New Species of Water Molds 
291 
The remarkable intercalary oogonium shown in fig. 8 is unique. 
Its single egg was 27.8 by 50 n in size and a large number of oil- 
drops were grouped at each end. An antheridial cell was also cut 
off at each end, but no antheridium could be made out. 
The peculiar jelly-like outer layer that De Bary noticed on the 
oogonia in October cultures was also seen by Humphrey in a few 
cases. By careful observation I have been able to make out this 
layer in the majority of young oogonia. It is probably present on 
all at a certain stage, but in clean cultures free from bacteria is 
very hard to trace. Its presence and outline is hardly discernable, 
except for the bacteria and other minute particles that stick to it. 
As remarked by Humphrey it is hardly possible that this hyalin 
gelatinous outer sheath can be a “ periplasm ” secreted from the 
oogonium contents, as De Bary suggests. It is more apt to be due 
to the gelatinization of a thin outer layer of the wall of the 
oogonium. 
In a typical clean culture in springwater on a mushroom grub 
the sporangia varied from 37 to 56 /j. in diameter, the majority 
being from 44 to 48 ^ broad. 
In figures 9 and 10 are shown sporangia of usual appearance. 
When the sporangia proceed at once to the formation of spores 
the discharge is usually at the tip (fig. 9). If a rest occurs, the 
immergence tube is as apt to appear at the base, as shown in 
fig. 11. After the first sudden release of pressure the spores do 
not rush out as in Achlya and Saprolegnia, but emerge much more 
quietly as they find the opening. The last ones often swim around 
a long time in the sporangium before finding an exit. The spores 
are pear-shaped, with two cilia at the small end. On coming to 
rest they round up. In fig. 12 are shown three normal spores and 
an anomalous double one with four cilia. This is not a case of 
fusion after emergence, but of imperfect segmentation of the 
protoplasm. I have often seen in species of Achlya the discharge 
of large lumps and iregular masses of protoplasm from the 
sporangia as a result of imperfect segmentation. Sometimes the 
whole mass may in Achlya be thus discharged as a single long, 
contorted rope (see below p. 300). Leitgeb 7 shows similar masses 
of protoplasm in Saprolegnia monoica (under the name of 
Diplanes ) . 
7 Jahrb. fur Wiss. Bot. 7: 357, plate 24, figs. 3-3. 1869. 
