Some nuclear phenomena in Venturia inaequalis.

The development of the aseoearp of Ventturia inagequalis (Cke.) -Wint. has beeni stuldied by Killian (1917) anld Frey (1924), both of wNlhoin reviewv, ed extensive literature dealin1g wTith sexuality in the Asco:mnyeetes. Their wiork has beeni reviewed by Keitt anid Palmiiiter (1938) in con-nectionl with stuldies on heterothallismnancd v7ariability in this fungus. Observations on the cytology of the imiiperfect stage of this organismhave been reported by -Wiltshire (1915) a,nd Nusbanin ancd Keitt (1938) in stuldies on hostparasite relationis. Receut work by Keitt, Palhu-iter, aucd Laugford (1938) ancd Keitt and LaI-angford (1940) on variability ancd iniherit,a,nee of this pathogen miiake desirable further investigation of t,he developmlent of the aseus and of nuclear phenomuenia in the vegetative niyeelinum, the coniidiopimore, anid the conidiuma. Such stuldies are report,ed in thie present paper.