New Observations on the Distribution and Morphology of the Amphipod,Gammarus ZaddachiSexton, With Notes on Related Species

As is well known, the species Gammarus zaddachi , established by E. W. Sexton in 1912 on material from European brackish and fresh-water localities, has caused great confusion among zoologists, as the characteristics distinguishing it from various related species, particularly Gammarus locusta, G. duebeni and G. pulex , have been very frequently disregarded. This confusion still persists to-day—that is amply shown by the material received for the present investigations from various museums.