308 Trow. — Observations on the Biology and 
terminology, even if an unsuitable one, may serve a good 
purpose if it aids us in rearranging our ideas concerning 
fertilization. No clear idea of this complicated question, 
though, will be gained while gametangia are confused with 
gametes and sporangia with spores. 
Summary. 
The conidia of this Fungus were found in rotten cress- 
seedlings in July, 1899, and the species has been cultivated 
as a saprophyte on sterilized potatoes, house-flies and cabbage 
leaves, &c., up to the present time (January, 1901). 
The species appears to be a pure saprophyte, all attempts 
to infect fresh cress-seedlings having failed. 
Pure cultures were obtained by infecting sterilized potatoes 
with material obtained from fairly pure cultures on rhubarb 
leaves. 
On potatoes, an aerial mycelium is freely developed, which 
remains sterile for weeks. If the culture is prevented from 
drying up, crops of conidia and oospores are ultimately 
obtained. 
An aquatic mycelium is produced in cultures grown on 
house-flies and bits of cabbage leaves immersed in water. 
The reproductive organs make their appearance when the 
culture is two or three days old, and as a rule the house-fly 
cultures produce conidia, and the cabbage-leaf cultures 
oospores only. 
The whole life-history has been carefully followed in moist- 
chamber cultures. The chief features, as determined by 
De Bary and others for the genus, have been verified ; but 
in addition it is clear (a) that De Bary erred in including 
the greater part of the periplasm in the oosphere, and in 
describing a sharp differentiation of periplasm and gonoplasm 
in the antheridium ; and ( 5 ) that the periplasm is digested 
and absorbed by the young oospore, which, in consequence, 
increases in size. 
The conidia and oospores invariably produce germ-tubes 
