212 Har tog. —Recent Researches 
one another, retreat from the cell-wall, and cease to be clearly 
separated. In liberation the spore-mass forms a cylinder and 
presses out, becoming thinner at the outer end, and only later 
at the base ; sometimes this column breaks up transversely 
into several, and finally these break up into separate spores 
often united by plasmatic threads ; as the spores pass out they 
group into a hollow sphere at the mouth of the sporange. 
In his ‘Nachtrag’ he insists strongly that my description of 
the liberation of the zoospores in Achlya polyandra is incorrect, 
and that they are not biflagellate as Cornu and I describe. 
This involves two points ; first of all the identity of my species 
with A. polyandra of Hildebrand (who founded the species in 
Pringsheim’s Jahrblicher, vii. 1867-8), and next whether I am 
justified in extending my observations to other species of 
Achlya. As to the first point, my species was identical in all 
characters with Hildebrand’s careful diagnosis ; while De Bary 
expresses grave doubts as to the identity of his 1 . As to the 
second point, the behaviour of the zoospores at and after 
liberation in another species, which I identify with Achlya 
recurva , Cornu, is exactly the same as in A. polyandra. Cornu 
ascribes flagella to the zoospores of Achlya generally, without 
particularising the species ; and a positive assertion of a trust- 
worthy observer is worth all the negative evidence in the 
world. I have always failed to see the flagella without iodine 
staining ; and Rothert has never definitely looked for them by 
staining at the stage of liberation 2 . We shall see later that 
there is independent ground for believing in their presence. 
Dictyuchus clavatus was also observed by Rothert. Its 
processes are essentially the same as in the other genera, 
except that the liberation is effected by the deliquescence of 
the sporangial wall when the spores slowly separate a little 
and at once encyst. Leptomitus lacteus shows the relations of 
Saprolegnia in the main. 
The oogonia, as seen in Achlya , show exactly the same 
1 Beitrage zur Morph, u. Phys. d. Pilze, Ser. IV. p. 49. 
2 As he has informed me by letter. 
