Studies on two Strains of Aphano—Myces Laevis found Occurring as Wound Parasites on Crayfish

SUMMARY

1.	Aphanomyces laevis De Bary has been found occurring as a mild, facultative parasite in the wounds of young crayfish (Cambarus Clarkit) kept in the laboratory.
2.	Two morphologically similar strains are described, one of which produces few zoöspores and many oögonia, the other of which forms few oögonia but many zoöspores.
3.	In identifying these strains as Aphanomyces laevis, the physiological variability of the species as reported by previous authors is considered. In view of this variability, the differences in the reproductive habits of the two morphologically similar isolates discussed in this paper are of interest.