In this paper I will try to solve the controversial points still existing in respect to the species Alcyonium palmatum Pallas, Alcyonium acaule Marion and Alcyonium brioniense Kükenthal. I found that A. brioniense has to be regarded a synonym of A. acaule, and that A. palmatum adriaticum Kükenthal, 1907, ( = A. adriaticum of Kükenthal, 1909) can neither be considered a geographical race nor a valid species. I wish to express my sincere thanks to Dr. L. D. Brongersma, director, and Drs. W. Vervoort and L. B. Holthuis, curators, of the Rijksmuseum van Natuurlijke Historie at Leiden, to Prof. Dr. H. Engel, director, and Dr. J. H. Stock, curator, of the Zoölogisch Museum at Amsterdam, for placing material of their respective museums at my disposal and for their kind assistance. My thanks are also due to my colleagues Mr. W. ter Spill, who revised my English, and Mr. G. J. Vrijmoeth, who performed for me the difficult task of making the photographs. OUTLINE OF THE LITERATURE CONCERNING ALCYONIUM ACAULE MARION AND A. BRIONIENSE KÜ KENTHAL In 1878 Marion distinguished between two types of Alcyonium, occurring in the Bay of Marseilles. The first type he called „les Alcyons des fonds vaseux", evidently since it is found on a muddy bottom. This type was characterized as follows: (a) the colony has a long sterile stalk (Marion, 1878, pl. 6 fig. 1); (b) the length of the colony is 23 cm and more; (c) usually the colour is palish, though sometimes it may be a dirty light-yellow, brown-red or bright vermilion; (d) the tegument is transparent and nearly colourless; (e) usually the zooids are colourless or slightly white or yellow, sometimes their spicules are reddish; (f) in the sterile stalk there are short,