Butler.—On Allomyces, a new Aquatic Fungus. 1029 
the Leptomitaceae is inevitable if we are to unite it to any of the recognized 
families of the Phycomycetes. 
There are, however, two characters of considerable weight which the 
new Fungus possesses in common with Gonapodya and less definitely with 
Blastocladia , which separate these three forms widely from the other 
Leptomitaceae. These are the composition of the cell membrane and the 
character of the zoospores. 
Of the authors who observed the two latter genera, Reinsch and Thaxter 
do not mention the composition of the membrane. Cornu (’ 72 , p. 15) 
stated that Monoblepharis (in which he included Reinsch’s Saprolegnia 
siliquaeformis — Gonapodya siliquaeformis , Fischer) is devoid of cellulose. 
Recently Petersen states that this is the case with both Blastocladia and 
Gonapodya . The new Fungus gives a t reddish yellow colour with chlorio- 
dide of zinc, the wall of the resting spores being particularly deeply stained, 
and can be sharply distinguished by this means from Saprolegniaceae 
[Saprolegnia and Achlya ), with which it is growing, the latter taking a clear 
blue colour. It is therefore in this respect more closely allied to Blastocladia 
and Gonapodya than to the other Leptomitaceae. Monoblepharis is the 
only other Oomycete giving a similar reaction. 
As regards the zoospores, the form observed in Pusa was constantly 
1- ciliate. Gonapodya also has i-ciliate zoospores, according to Cornu and 
Thaxter, though the latter states that they have sometimes seemed to be 
2- ciliate. Reinsch and Petersen do not specifically remark on this point. 
In Blastocladia there appears to be some doubt. Thaxter describes the 
zoospores as normally s-ciliate, but Sometimes only one cilium can be found ; 
Petersen says that they are i-ciliate. In shape and behaviour all three are 
allied, those of Gonapodya in particular having, like Allomyces , a short 
period of amoeboid movement after emerging from the sporangium. In 
the other Leptomitaceae the normal 2-ciliate zoospore of the Oomycetes 
is found. 
These three forms are therefore similar in that they possess certain 
important characters differentiating them from the other members of 
Schroeter’s family Leptomitaceae. Whether Gonapodya and Blastocladia 
were rightly included by Schroeter in this family is uncertain. Thaxter 
(’ 96 , p. 325) doubtfully includes Gonapodya , but excludes Blastocladia . 
Petersen makes a separate family for each, Gonapodyaceae and Blasto- 
cladiaceae. Allomyces is clearly allied to the latter and serves to unite it 
more closely with the true Leptomitaceae. On the whole, though the 
character of the membrane is such as to prevent dogmatism, the new form 
tends to strengthen Schroeter’s view and to indicate real affinity within the 
limits of the family as defined by him. 
In 1907 I suggested that the peculiar Phycomycete Monoblepharis , the 
only known Fungus with motile sperms, was related more to the Leptomi- 
