On the Hydroids and Medusae Bougainvillia Pyramidata and B. Muscoides

Abstract

SUMMARYThe hitherto unknown hydroid of the anthomedusa Bougainvillia pyramidata has been found in the Firth of Clyde, and medusae from it have been reared to maturity. The hydroid and the stages of development of the medusa are described and figured, and the species is compared with B. ramosa. The seasonal occurrence and distribution of the medusa are discussed.The hydroid Bougainvillia muscoides (M. Sars) has also been found in the Firth of Clyde. Medusae have been reared from it, and a description, with figures, of the stages of development is given. The specimens found in 1901 in this area and described by Browne as Thamnitis sp. are shown to be young medusae of B. muscoides. The geographical and bathymetric distribution of the species and the seasonal occurrence of the medusa are described and discussed.