76 Proceedings of Indiana Academy of Science 
ing a new zodsporangium in the old one, although the old zodsporangium 
is probably due to external conditions, as stated by Pfeffer,* in various 
plants, and these may even prevent at times the formation of sporangia. 
A deficiency of food, says Pfeffer,; may cause the formation of zo- 
ospores or oOspores in Saprolegnia, whereas with some substances no 
reproductive organs are formed and again with other food substances 
the formation. of odgonia are favored... The various conditions also 
account for the difference in the latent period of the spores of this 
plant, which, as stated by Pfeffer? and observed by different investi- 
gators, ranges from 8 to 10 days as observed by Klebs® and 45 to 145 
days according to de Bary.* Also the zodspores are especially influ- 
enced by various conditions, among these being the attraction by certain 
substances of which the phosphates are very active.° 
Inasmuch as the representatives of this division of the fungi are, 
like some other plants, rather susceptible to some or all of the above 
mentioned conditions, they tend toward some variation from the forms 
ordinarily observed. In many cases fish-of various kinds are attacked 
by this fungus and extensive epidemics, as stated by de Bary,’ of fish 
in the English and Scottish rivers and elsewhere have occurred. The 
writer has observed, however, and can confirm de Bary’s' statement, 
namely, “that healthy gold fish may continue lively and free from the 
Fungus for months in water in which Saprolegnieae kept purposely in 
large quantities were forming an abundance of spores.” 
The writer has observed insects of various kinds on which, on one 
occasion, a heavy growth of Saprolegnia was present. The zodsporangia 
of all of these were formed in the usual manner at first, but when new 
sporangia were being produced in the first ones some departures from 
the usual order were noticed. This will be made clear by an observa- 
tion of Figure 1. Usually, as is well known, but one new zodsporan- 
gium is formed by growing up through the hull of the old one in the 
ordinary way. In this case, however, four new zodsporangia had formed 
within the hull of the original one. The hulls of these sporangia were 
still held together and attached to the main branch or filament of the 
fungus but were empty. A small part of the contents was left in the 
third one that was newly formed. The old zodsporangial cavity con- 
tained the upper parts of the new sporangia that had grown through it. 
In another instance a single tube had grown up through the old 
sporangial cavity in the usual fashion. On the end of the tube which 
projected through the original apical opening of the old zodsporangium, 
a large, round swelling was present which resembled as to form and 
size the ordinary odgonia. This departure from the usual behavior of 
the formation of zodsporangia is shown in Figure 2. The further de- 
* Pfeffer, W., Physiology of Plants, 1903, p. 39. 
+ Pfeffer, W., 1. c., p. 116. 
1 Pfeffer, W., 1. c., p. 117. 
2 Pfeffer, W., 1. c., p. 208. 
3 Klebs, Jahrb., f. Wiss. Bot., 1899, Bd. 38, p. 571. 
4De Bary, Vervil, Morph. u. Biol. des Pilze, 1884, pp. 356-370. 
5 Pfeffer, W., 1. c., Vol. 3, 1906, p. 348. 
6 De Bary, Comp. Morph. and Biol. of the Fungi, 1887, p. 375. 
7De Bary, 1. c., p. 375. 
