Interstitial Syllidae (Annelida: Polychaeta) from Mahe (Seychelles)

About 500 specimens of Syllidae were collected during two field expeditions in the years 1999 and 2000 to Mahe (Seychelles). Most of the specimens were collected on fringing coral reefs. others were dredged from deeper coralline sands (22-34m). Eighteen genera and 39 species of Syllidae were found. of which four are herein described as new to science: Parexogone anseforbansensis n. sp .Parexogone seychellensis n. sp ., Sphaerosyllis sanmartini n. sp. and Typosyllis pselldoheterosetosa n. sp. Descriptions with illustrations and micrographs are provided for the new and other interesting species. The majority of the species are really interstitial. living in sandy habitats; the others were found under and inside beach rocks and dead corals.