174 
Wager . — The Life-history and 
The majority of the genera and species of the Chytridiaceae belong to 
the first group. In the second group there are only four genera, three of 
them, Diplophysa , Polyphagus , and Urophlyctis being placed in the sub- 
family Oochytriae, and a single genus, Zygochytrium , in the sub-family 
Zygochytriae. 
The three genera of the Oochytriae resemble in their vegetative 
characteristics certain members of the first group, and are in fact only 
distinguished from them by their sexual reproduction. There seems to be 
no good reason, therefore, why the Oochytriae should be maintained as 
a separate sub-family, as the genera included in it might very properly 
be included in the other sub-families. Thus Diplophysa ( Olpidiopsis ) 
would be placed in the Olpidiae, and Urophlyctis in the Cladochytriae. 
Polyphagus may perhaps be regarded as intermediate between Chytridium 
and Rhizidium , the two genera of the Rhizidiae. Zygorhizidium Willei , 
described by Loewenthal, would be included in the Rhizideae. This 
rearrangement of the genera would simplify the classification of the 
Chytridiaceae, and the following key, showing how the various sub-families 
would then be differentiated, may be useful. 
Key to the Sub-families of the Chytridiaceae. 
i. Resting spores produced asexually, rarely by the 
copulation of swarm spores .... 
i. Sexual spores formed by conjugation, as in Muco- 
rineae ........ 
1 . Mycelium absent ....... 
2. Mycelium present ....... 
3. Sporangia always single and formed outof the whole 
mass of the thallus 
3. Sporangia in groups or sori ..... 
4. Mycelium in the form of delicate transient strands 
4. Mycelium hypha-like, permanent .... 
5. Mycelium giving rise to one terminal sporangium 
only, never intercalary 
5. Mycelium spreading, often through several cells ; 
sporangia terminal and intercalary 
Occurrence and Habit. 
Polyphagus Euglenae appeared in abundance in the spring of 1898 on 
cultures of Euglenae obtained from the Sewage Farm at Keighley in 
Yorkshire. The Euglenae from which the cultures were made formed 
a bright green scum on the surface of the drying-up mud or sediment left 
on the filter beds. The cells were found to be in a resting and slightly 
Zygochytriae. 
3 
4 
Olpidiae. 
Synchytriae. 
5 
Hypochytriae. 
. Rhizidiae. 
Cladochytriae. 
