XXII.—A Quantitative Study of Spermatozoan Nucleus Length inDrosophila melanogaster(Meig).

Abstract

SynopsisA squash-preparation technique for the measurement of nucleus lengths in permanent preparations of the spermatozoa ofDrosophila melanogasteris described. Prefixation gave longer nuclei, but the degree of pressure used in making the squash did not affect nucleus length. Variation in nucleus length between the spermatozoa of a male was fairly high (coefficient of variation 14 per cent). Smaller, though significant, differences existed between means of males within culture bottles, but there were no significant differences between means of duplicate culture bottles. There was a little evidence of heterogeneity of within-male variances. A logarithmic transformation of data before analysis was indicated. These observations provide a hitherto missing background for planning experiments in quantitative variation designed to throw light on genetic and other factors affecting the dimensions ofDrosophilaspermatozoa.