The marine Amphipoda of the Plymouth area, as a group, were last given attention in the middle 1930's by Crawford (1936,1937). Renewed investigation after the lapse of 15 years has indicated that knowledge of species present was by no means complete, or that some changes have occurred in the interval, or both. In a recent survey of the amphipod fauna of the Isle of Man, Jones (1948) found no indication of the existence of undescribed species, nor even of known species previously unrecorded from Britain. The experience at Plymouth has been quite the reverse.