232 SOME NOVA SCOTIAN AQUATIC FUNGI. MOORE. 



cultures the larger filaments or branches may give rise to fine 

 branches terminating in oogonia containing only one or two 

 oospores and with walls, showing but a few blunt protuberances. 

 In one culture this species was attacked by a parasite identical 

 with or closely resembling Olpidiopsis saprolgnice A. Braun. 



A species which bears a very close resemblance to the pre- 

 sent one is that described and figured by Dr. Humphrey 6 , as 

 Saprolgnia treleaseana. The generic position of that species 

 was determined from the observation of one empty sporangium 

 by Dr. Trelease. Its vegetative habit is, according to Dr. 

 Humphrey, very Acklya like. In all of the cultures made of 

 A. acadiensis the sporangia were produced in sufficient 

 numbers, although sometimes scarce, to render its generic posi- 

 tion readily established. Through the kindness of Dr. Johnston, 

 of Johns Hopkins University, I have been enabled to examine 

 the only preparation of 8. treleaseana in Dr. Humphrey's col- 

 lection. This preparation shews oogonia and resting sporangia j 

 which correspond closely with those of the present species. No 

 mention is made by Dr. Humphrey of the pitting of the walls 

 in 8. treleaseana and as the pits are always obscured by the 

 outgrowths, and are generally only evident after treatment with 

 chlor-zinc-iodine, no comparison could be made in this respect 

 between the two species. I have provisionally described the 

 present form under a new name, but further investigation of 

 Dr. Humphrey's species in its type locality may shew that they 

 are identical, in which case the older specific name would pre- 

 vail, and it would be known as Achlya treleaseana. 



Genus Aphanomyces deBary. 



A. stellatus deBary (Fig. 20). Hyphse delicate, 6/^-7 //. wide, 

 little branched. Zoospores forming in a single row and after 

 escape collecting in a cluster at the mouth of the sporangium. 

 Oogonia terminal, the walls with blunt outgrowths giving a 

 star-like appearance. Oospores single, filling the oogonium. 

 20Ai-25/u, in diameter. Antheridia present, one to each oogo- 



