The Plymouth Offshore Medusa Fauna

Abstract

The composition of the medusa fauna in offshore waters off Plymouth is reviewed. A table is given showing the months in which the different species have been recorded and those months in which they are most abundant. A preliminary list has been drawn up attempting to discriminate between those species which are regularly indigenous off Plymouth and those which are brought from elsewhere by water movements. The results of weekly hauls with the 2 m. stramin ringtrawl during the years 1930-7 inclusive are given. The years 1935, 1936 and 1937 have been noteworthy for the paucity of all species of medusae. Observations on the structure and biology of certain species of medusae are recorded.