ISOACHLYA 87 



Cultures of No. i of April 25. 191 8: 



On pieces of boiled corn grain (repeated -several limes): C.rowtii fairly vigorous to very 

 vigorous— over a centimeter in length; hyphae somewhat wavy and curled; sporangia 

 produced normally as on grubs; many oogonia with eggs formed. 



On grubs in pure water in ice box: Invariably produced many sporangia and spores. 

 Check cultures were kept going out in the laboratory and though the room was quite 

 hot (y° C.) they were \ery \igorous. They produced no sporangia, however. 



On corn meal agar: Growth fairly vigorous; sporangia present; many oogonia with eggs; 

 no bacteria visibly present. Same result with No. l of June 22, 1918. 



3. Isoachlya eccentrica n. sji. 



Pl.\te 24 



Threads long, slender, little branched, 6-i8.5tx thick, most about 

 1 2-1 5yL, growth vigorous on termite ants, bits of boiled corn grain and on 

 agar plates; length on corn grain up to 8mm., on a termite ant up to 4mm. 

 tips pointed and clear. On corn grain many or most of the tips become 

 sporangia of a regula*- cylindrical shape, with a distinct papilla, 30-45 . X 

 142-400;^, at times bioader in the middle, again near the tips. On termite 

 ants the sporangia are less regular, with several apertures in most cases. 

 Proliferation of sporangia not common, when present never internal as 

 in Saprolegnia, but irregularly from below, as in Achlya j^nd Pythiopsis. 

 Dictiosporangia observed a few times. Spores diplanetic, io-ii;j. thick 

 when at rest, emerging rather slowly with the cilia directed backward, 

 then reversing and swimming sluggishly for a very short time, many 

 coming to rest in the immediate neighborhood of the sporangium; 

 shape and contents as in Saprolegnia Gemmae plentiful, following the 

 sporangia, very irregular in size and shape, after a time forming spores. 

 Oogonia spherical as a rule, seldom oval, 15-40;^. most about 30-3511. thick, 

 usually single, at times in chains of four or five; commonly borne on 

 short lateral stalks which are from one-half to twice as long as the diameter 

 of the oogonia; often as well on the tips of threads which have proliferated 

 through empty sporangia, and in such cases net rarely formed inside 

 the sporangia; sections of old threads may also become oogonia. _ Wall 

 colorless, smooth, many without pits, some with a few large, conspicuous 

 ones. Eggs usually one, often two, rarely three or four; i2-3i;x thick, 

 most about 20-25;jl, eccentric, with a single large oil drop at maturity. 

 Antheridia none. 



Found but once, without intermixture of other forms, in a small 

 shallow pool with decaying leaves, behind the power house. Chapel Hill, 

 N. C, December 2, 1921 (F. A. Grant, coll.). 



The present plant is remarkable as being the only species of the family 

 with a typically eccentric egg, in which the spores swim away on emerging 

 (see remarks under Saprolegnia anisospora). Except for the eccentric 

 egg all other characters are those of Isoachlya and we therefore refer it 

 to that genus. The nearest relative seems to be /. unispora which easily 



