Occurrence of an intersex condition in the roach Rutilus rutilus (L)

The roach, Rutilus rutilus, is normally a dioecius species. During an experimental study of reproduction in this species, a condition of apparently functional intersex was discovered. Anatomically the gonad was a testis, exhibiting various normal stages of spermatogenesis. A group of oocytes was found during the microscopical examination of the gonad, interspersed between lobules of normal testicular tissue. A few small oocytes were found to be in the chromatin‐nucleolus stage, while the rest were in the perinucleolus stage. In addition, some large oocytes with an average diameter of 40 μm were randomly distributed among the lobules of the testis.