's RIJKS MUSEUM VAN NATUURLIJKE HISTORIE — LEIDEN. 247 



the apex of the acicula emerges; its bristle-fascicle consists dorsally of 

 faintly heterogomph setose bristles, stouter than the notopodial ones and 

 of some heterogomph falcate ones. The ventral part of this fascicle con- 

 tains chiefly heterogomph falcate bristles, the terminal piece of which is 

 only denticulated in its basal part; moreover there occur some hetero- 

 gomph setose bristles, with a terminal piece, ciliated along the total edge. 

 Several species of Lycastis already have been descripted from distant 

 parts of the world (Brasil, Senegal, Honolulu etc.), but they are not all 

 distinguished from each other by well defined characters. Lycastis-specimens, 

 found by Mr. Ouwens some years ago in a fresh water pond of the 

 Botanical garden of Buitenzorg, were identified by myself with L. ha- 

 waiiensis Johns. ; they are much more slender than the Merauke-worms 

 and they lack entirely the notopodial bristles, the acicula only being 

 present. ! ) 



Gymnorhynchus nov. gen. 



Prostomium bearing tentacles, palps and two pairs of eyes, as in Nereis. 

 Proboseis without horny paragnaths, only armed with soft papillae and 

 with a pair of jaws of typical nereid form. Parapodia conspicuously 

 biramous, with a high, conical, dorsal ligule, bearing the dorsal cirrus 

 upon its tip or somewhat beneath it. No true falcigerous setae. In the 

 epitocous form no special lamellae developed, but the original lobes pro- 

 vided with cultrate setae of a special shape. 



Gymnorhynchus sibogae n. sp. 



Siboga-expedition, Stat. 75, off spermonde bank, Strait of Makassar. 

 Among the worms of the above-named station I met with two Nereis- 

 specimens, characterized by the elongated appearance of the parapodial 

 lobes. In the anterior body-region the parapodium is provided with a 

 slender, conical, dorsal ligule, that reaches nearly to half the length of 

 the elongated, median ligule and bears beneath its tip the dorsal cirrus, 

 far extending beyond its extremity. The ventral ligule is short, conical, 

 hardly extending beyond the extremity of the ventral lobe, that is pro- 

 vided with an obtusely conical anterior lip and a rounded, circular 

 posterior one. The aciculae are black, the bristles pale yellowish coloured. 

 The neuropodial fascicle does not contain true setae falcigerae, but in- 

 stead of these some faintly heterogomph setigerous bristles, with a short, 

 lanceolate .terminal piece. In the 16th parapodium and the succeeding 



1) Bulletin du Département de l'Agriculture aux Indes Néerlandaises, n°. XXV, where a 

 review of the littérature is mentioned. 



