A histological and cytological examination of the male gonads of numerous ex-fissiparous specimens of Dugesia gonocephala s.l. (Tricladida Paludicola) from various European and extra-European localities showed that spermatogenesis is notably altered. Despite inter-populational variations, the majority of the specimens had small testicular nodules containing spermatogonia, spermatocytes I and rare spermatids; only a minority had larger follicles occasionally containing small bunches of sperm which, however, were much fewer than those found in the testicles of normally sexualized individuals. The anomalies found in the male gonads, just as those observed in the female gonads during previous research, are due to fission-controlling factors which are present although inhibited in the ex-fissiparous specimens.
Histo-cytological study of ex-fissiparous planarian testicles (Tricladida paludicola)
DERI, PAOLO
1980-01-01
Abstract
A histological and cytological examination of the male gonads of numerous ex-fissiparous specimens of Dugesia gonocephala s.l. (Tricladida Paludicola) from various European and extra-European localities showed that spermatogenesis is notably altered. Despite inter-populational variations, the majority of the specimens had small testicular nodules containing spermatogonia, spermatocytes I and rare spermatids; only a minority had larger follicles occasionally containing small bunches of sperm which, however, were much fewer than those found in the testicles of normally sexualized individuals. The anomalies found in the male gonads, just as those observed in the female gonads during previous research, are due to fission-controlling factors which are present although inhibited in the ex-fissiparous specimens.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
