Among the worms of our collections I met with two specimens of the genus Eudrilus, kindly presented to our Museum by Mr. C. J. Heering from Surinam. The genus Eudrilus was named by Perrier 2), who described three species: E. Lacazii (from Martinique), E. decipiens (from the Antilles) and E. peregrinus (from Rio Janeiro). Last year Mr. Beddard received from New Caledonia a dozen of earthworms, belonging to the same genus, which he named E. Boyeri 3). The genus Eudrilus, though agreeing in many characters, viz.: the arrangement of the bristles, the presence of a muscular gizzard, the form of the vascular system, with Lumbricus, is distinguished from it by the remarkable structure of its genital organs. Beddard published a careful account of the anatomy of these organs 4), which however differs in several respects from Perrier’s earlier description; therefore 1 thought it very interesting to examine if the structure of the genital organs in our specimens did correspond with his description. Moreover through the kindness of Mr. Layard I was able to dissect also some individuals of E. Boyeri Bedd. from New Caledonia. The largest of our two Surinam-specimens measures 170 m.m. in length, the number of its segments being about 200. The cephalic lobe is club-shaped, impinging till the middle of the buccal segment. There is an annular girdle, occupying six segments, from the 13th to the 18th, quite like in E. Lacazii Perr. The female genital pores are situated on segment 14, in the series of the dorsal bristles, the male genital pores lie on segment 17, in the series of the ventral bristles; the last pores are rather large and surrounded by a ridge, which is radiately folded.