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The distribution of genes in the second and third chromosomes of Drosophila melanogaster suggests that crossing-over may be influenced by the spindle fibre at least in neighboring regions. The disparity between the genetic and cytological maps of these chromosomes especially in the spindle fibre regions (Dobzhanzky2'3) is consistent with such a view. Sturtevant4 suggests from studies of crossing-over in Drosophila stocks homozygous for inverted sections of the autosomes that crossing-over in a given region is a function of the material in that region rather than of its position in the chromosome. He found no significant changes in amount of crossing-over with change in position of a section of a chromosome with respect to the spindle fibre or the end of the chromosome. Muller and Stone5 in a study of crossing-over in the case of a homozygous inversion in the X-chromosome of Drosophila apparently found that the regions in the inverted section gave normal crossing-over. However, since in none of these cases of homozygous inversions did the inversion include regions close to the spindle fibre, the possibility remains that the spindle fibre influences crossing-over in regions close to it. Dobzhansky6 studied crossing-over in a homozygous III-IV translocation in Drosophila (designated as translocation-c) and found' no significant differences from normal controls. However, the regions which .might have been expected to be influenced by the spindle fibre were not studied. At the suggestion of Professor Dobzhansky, the Writer has made additional studies of crossing-over in flies homozygous for this translocation.-The results are reported in the present paper. In the translocation stock under consideration a distal segment made up of about three-fourths of the right limb of chromosome III (cytologically3) is broken off and attached to chromosome IV The break in chromosome III is close to and to the left of the curled gene (0.7 unit according to Dobzhanky's data3 and somewhat closer according to results obtained by the writer). Accordingly, in the homozygous translocation flies the section of the third chromosome including curled and regions to the right is closer to a spindle fibre (of the fourth chromosome) by a cytological distance equal to about one-fourth the length of the right limb of chromosome III. Genetically this distance represents about 2 crossover units (standard map7).