SUMMARYIn this study, we have attempted to detect and describe patterns in the arrangement of gene loci within chromosomes of a metazoon. Known loci For all these properties, there is little, if any, evidence of clustering between known loei that are not close enough to belong to the same 10-locus group. Our analysis has, however, revealed evidence confirming that some properties show a tendency to cluster within a 10-locus group. Even this tendency is not strong, except for some of the morphological properties.However, it is apparently at variance with the findings of Elston and Glassman (1967), based on fewer data.