THE REPRODUCTIVE PATTERNS OF THE FIVE FIJIAN SPECIES OF SEPTARIA (PROSOBRANCHIA: NERITIDAE)

The reproductive systems of the five Fijian species of Septaria(S. lineata, S. macrocephala, S. porcellana, S. sanguisuga,and S. suffreni) are described. It was found that the originaldescription of the shell of S. suffreni by Récluz (1841)applied only to male specimens. The septum of females lackeda tongue-like projection and as a result female S. suffrenihave in the past been mistaken for specimens of S. macrocephalaand S. porcellana. A spermatophore sac with spermatophores waspresent in female S. lineata, S. sanguisuga and S. suffreni,but was absent in female S. macrocephala and S. porcellana.The spermatophores produced by the three species differed inshape, size and in the number present in the spermatophore sac.The penis of S. lineata, S. sanguisuga and S. suffreni was longand fleshy for manipulating spermatophores, while those of S.macrocephala and S. porcellana consisted of a flap of foldedtissue adapted for direct transfer of sperm into the vaginalopening. Male and female individuals of all sizes were presentin S. lineata, S. sanguisuga and S. suffreni populations. Bothmale and female young were present in S. porcellana populationsbut individuals over 18 mm long were all female. In S. macrocephalapopulations, young less than 13 mm were all male, while allspecimens longer than 15 mm were female, suggesting that thisspecies is protandrous. (Received 4 December 1990; accepted 7 May 1991)