294 
Mycologia 
cymosa is quite rare. Humphrey saw two eggs only once and 
my cultures of that species have not produced any such oogonia. 
De Bary says that as many as three eggs may occur in P. cymosa 
but their appearance is evidently of great rarity. 
In order to judge of the significance of the peculiar behavior 
of the spores in Achlya paradoxa it will be useful to review the 
variations in behavior in sexual reproduction in the Saproleg- 
niaceae as recorded in the literature. 
In the case of Achlya a departure from or modification of the 
usual grouping of the spores at the sporangium tip has been 
recorded in a few instances. In the first place it must be remem- 
bered that the spores in this genus are not perfectly quiescent 
during and immediately after emergence. A slight amoeboid 
motion is observable at all times from their initial formation to 
the appearance of the encysting membrane. Added to this is a 
certain feeble jerking and rotation due to the presence of cilia, 
that has been recorded by several observers since Cornu 8 first 
described it in 1872. On page 11 of his monograph Cornu says 
that these cilia have just enough agility to cause the escape of the 
spores from the sporangium, thus implying that they are the 
cause of the escape, a point that has been considerably discussed 
and which I shall take up at another time. The presence of 
cilia on the emerging spores of Achlya is strongly asserted by 
Hartog 9 who also predicts that they will be found in all species of 
Achlya and Aplianomyces . 10 
He also says in the first of these papers that the spores of 
Achlya after forming a ball revolve on their long axils for a short 
time before the cyst is formed, and that sometimes a few spores 
will detach themselves and swim away a short distance. In the 
second paper he says that “ When the sporange is discharged near 
the margin of the hanging drop, or in a thin layer of water on a 
slide, we constantly see single spores escape from the mass, swim 
away, and encyst apart.” This important observation has been 
frequently overlooked by subsequent workers, but I can confirm it 
8 Monographic des Saprolegniees. Ann. Sci. Nat. V. 15: 5. 1872. 
9 Quart. Jour. Micr. Sci. 35: 427. 1887. 
10 Ann. Botany 2: 201. 1888. 
