The hydroid and the medusaBougainvillia principis, and a review of the British species ofBougainvillia

Abstract

The hitherto unknown hydroid of the anthomedusaBougainvillia principishas been found in the Firth of Clyde, and medusae from it have been reared. The hydroid and the stages of development of the medusa are described and figured. The medusa is commonly present in the plankton in this area, and its seasonal occurrence is described.The historical development of our knowledge ofB. principisand ofB. superciliaris, which have been confused, is discussed. The hydroid and the young medusae ofB. principisare shown to be identical with those described by Hartlaub and attributed by him toB. superciliaris.Several doubtful speciesof Bougainvilliamedusae described from British waters are considered and are identified with accepted species.Medusa ociliaandM. duodeciliaare probably synonymous withBougainvillia pyramidataandB. principisrespectively; andB. nigritellais identified withB. muscoides, B. simplexwithB. principis, B. dinemawithB. britannica., andB. charcotiwithNemopsis crucifera, itself a probable synonym ofN. bachei.The medusaB. alderiis a probable synonym ofB. ramosa.The hydroids and the medusae of the British species ofBougainvilliaare reviewed and compared; and records ofB. superciliarisandB. maclovianaare given.