Notes on Eurydice (Isopoda, Flabellifera) from the Netherlands

INTRODUCTION During his investigation of the amphipod fauna of the sandy beaches of the Netherlands, Mr. W. J. M. Vader, formerly of this institute, met with two species of Eurydice Leach, 1815. Besides the common Eurydice pulchra Leach, 1815, he found a second species in smaller numbers. Because Giordani Soika (1955) as well as Renaud-Debyser & Salvat (1963) recorded Eurydice affinis Hansen, 1905, and E. pulchra from comparable beaches in northern France, Mr. Vader asked Dr. B. Salvat for some specimens of the former species for comparison. When these specimens arrived, Mr. Vader had left our laboratory. He was kind enough to entrust me with the further study of the Eurydice problem, for which I am most indebted to him. Further I want to thank Dr. L. B. Holthuis, Rijksmuseum van Natuurlijke Historie, Leiden, and Dr. B. Salvat, Muséum National d'Histoire Naturelle, Paris, for material, and Messrs. A. J. J. Sandee and L. de Wolf for their help in the field-work. The genus Eurydice is well known from the southern part of the North Sea. As early as 1778 Slabber described his "Agaat Pissebed" from the Dutch island of Walcheren. From the figure that he gave we can conclude with certainty that his animal belongs to E. pulchra. Holthuis (1956) still mentioned this as the only species of the genus from the coast of the Netherlands. In another publication Holthuis (1950) reported the occurrence of Eurydice spinigera Hansen, 1890, in the southern North Sea. E. affinis is here recorded for the first time from the Netherlands and the North Sea. The species was already known from Wissant (Pas de Calais) in France, just at the southern entrance of the North Sea (Giordani Soika, 1955;