The detection, in unordered octads, of 6+:2m and 2+:6m ratios with postmeiotic segregation, and of aberrant 4:4s and their use in corresponding-site interference studiesBY AGLAIA GHIKAS AND B. C. LAMBDepartment of Botany, Imperial College, London SWl 2BBVol. 29, No. 3 p. 273.The first line should read ‘originally PD or NPD 4:4(4)s,’.Sterile mutation in Drosophila melanogasterBY TAKAO K. WATANABE AND WON HO LEENational Institute of Genetics, Mishima 411, JapanVol. 30, No. 2.p. 110, second line: for ‘Avery Period’ read ‘P. J. Avery’.p. 111, 4 lines from foot of page: formula should readp. 112, line 4: start of line should readThe contribution of plasmid and host genes to plasmid-mediated interference with phage growthBY VICTORIA HUGHES AND G. G. MEYNELLBiological Laboratory, University of Kent, Canterbury, Kent CT2 4tNJ, EnglandVol. 30, No. 2.p. 180, line 12: ‘2000μg streptomycin’ should read ‘200μg streptomycin’.The basis for an apparent auxotrophy for reduced sulphur metabolites in sF−mutants of Aspergillus nidulansBY HERBERT N. ARTS, JR.Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, EnglandVol. 30, No. 2.p. 209, note added in proof line 9: ‘does not protect sF-211 strains’ should read ‘does protect sF-211 strains’.