Lycastis meraukensis n. sp. Dr. J. W. R. Koch, member of the New-Guinea expedition of the Kon. Nederl. Aardrijkskundig Genootschap in 1904, found at Merauke in decayed wood of the Sago-palm 9 specimens of this worm, viz. 2 large ones, one of which is incomplete and 7 smaller ones. Unfortunately it is not mentioned whether the tree was met with in fresh or brackish water of the river or in salt water at the sea-shore. The dorsal side of some of the worms is dark flesh-coloured, whereas a red brown ring occurs around the anal segment. The largest specimen measures about 150 mm. in length and has a breadth of 7 mm. in the median body-region (without the parapodia); the number of its segments amounts to 170. One of the smaller specimens has a length of 60 mm. and consists of about 150 segments. The head is more broad than long, rounded trapezoidal, provided with a longitudinal median groove. The eyes are situated laterally, in front of the posterior margin of the head; the external of each pair is the largest and it is placed somewhat more anteriorly than the internal. The antennae are short, conical; the palps consist of a stout basal part and a small, papilliform, distal joint. The maxillae are short and stout, provided with six teeth. The longitudinal diameter of the buccal segment is as long as that of the succeeding segment or somewhat shorter. The longest tentacular cirrus reaches to the 2nd or 3rd segment. The Merauke-worm is not slender, rather coarse and it belongs to that group of Lycastis-species, which have the dorsal cirrus enlarged and flattened, to form a leaf-like structure; as the cirri of the succeeding segments are overlaying each other, the worm somewhat resembles a