The last description of the coral Stylaster flabelliformis (Lamarck) appeared a century ago (Milne Edwards & Haime, 1857, p. 129). The cited authors listed in the genus Stylaster six at the time well-defined species, two of which, S. flabelliformis and S. gracilis, were characterized by having the "calices" exclusively on the lateral surfaces of the branches. From a modern point of view in the cited publication the specific characters were little clearly defined, consequently Broch (1936, p. 11) had to observe that the identity of S. flabelliformis is uncertain. Fortunately the species is well represented in the collections of the Paris Museum; during a visit in September, 1954, I made notes on the large colonies, while some small fragments were taken to Leiden for examination of the finer structures 1). Since the description of the coral (Lamarck, 1816) the name Stylaster flabelliformis (originally Oculina flabelliformis) has appeared in numerous papers, as shown in the following list (cf. Boschma, 1957, p. 9). Though the greater part of the references here noted are real synonyms, there are a few data of problematic reliability, as shown in the discussion following the list. Stylaster flabelliformis (Lamarck, 1816) Coralium album, lapideum, densum ac compactum; ramis laevibus, teretibus, multum divisis Seba, 1761, p. 204. Oculina flabelliformis Lamarck, 1816, p. 287; Deslongchamps, 1824, p. 575; De Blainville, 1825, p. 355; De Blainville, 1830, p. 345; Gray, 1831, p. 37; De Blainville, 1834, Ρ- 380; Deshayes & Milne Edwards, 1836, p. 457; Milne Edwards, 1849, Atlas, Pl. 83bis; Milne Edwards & Haime, 1849, p. 69; Milne Edwards & Haime, 1850b,