抄録
A comparative study of the chromosomes during spermatogenesis of four species of Diplopoda (Myriapoda) belonging to two families has been made. The diploid chromosome numbers of the described species vary from 12 to 24. In addition to the variation in numbers, the cytology of diplopods offers many points of interest. In all the species studied all the chromosomes are acrocentric. The male is the heterogametic sex and the sex-chromosome mechanism is of the XY type. The sex-chromosomes are characterized by their heteropycnosis and also by their differential behaviour, exhibiting prereductional division and lagging during meiotic divisions.
