Septaria suffreni: The only Septaria species with obviously sexually dimorphic shells. Shell up to 30 mm long, mean w/l ratio 0.74, mean h/1 ratio 0.34. Shell symmetrical, cap-like, apex outside the posterior edge of the shell. Ground colour yellow-green with variable markings - transverse wavy lines, fine triangles fading in older individuals, zigzags to only a few lines. Ventral surface of shell white to gray, muscle insertion scars prominent and darker. Septum on posterior edge orange. Apex small and often eroded. Dimorphism: Male shell often narrower than the female and the inner edge of its septum has a central tonguelike projection. Female septum edge straight . Male and female individuals are the same size and populations have the same number of each sex Operculum: Orange-pink and narrower in male. The posterior edge has a dark orange horn border and it is wider than the anterior end with the rib.

Septaria suffreni: MARTENS (1881) considered that RECLUZ'S N. suffereni and N. freycineti were synonyms and chose the name N. freycineti. RIECH (1923), on the other hand, thought the South East Asian N. freycineti from Sulawesi was a synonym of N. cumingiana and therefore used S. suffreni for the South Pacific species. The probable type specimens of N. suffreni are from Ovalau, Fiji. And the only other records of this species are from the South Pacific islands of Fiji, Samoa, New Caledonia and Vanuatu. The holotype of N. freycineti is the only record from Indonesia or anywhere else in South East Asia. RECLUZ gives its locality as 'Les marais de Makassar' - the swamps of Macassar -, Sulawesi. On the other hand, S. suffreni of the Pacific islands occurs on stones and rocks in fast flowing streams, and not in swamps. It is, therefore, not likely that RECLUZ'S N. freycineti is a synonym of S. suffreni or is a valid species.
Shell dimorphism in the species has led authors to confuse the females with S. porcellana, S. bougainvillei and S. macrocephala (STARMUHLNER, 1976; HAYNES, 1988). S. suffreni is the only one of these four species that produces spermatophores. FRANC (1957) confused female S. suffreni with S. luzonica because both have a pointed apex and a yellow-orange septum. Male S. suffreni can be mistakenly identified as S. cumingiana as its shell also has a similar, although usually smaller, projection on its septum. If the operculum is present there is no confusion as the operculum of S. cumingiana has two ribs while that of S. suffreni has only one.

Septaria suffreni: Range: Fiji, Samoa, New Caledonia, Vanuatu, It is the most abundant Septaria species in Samoa. On stones and rocks from tidal regions to well inland (50 km).