27 



does not reach till its distal extremity and consists of a rather thick brownish coloured, basal part, 

 and a thinner terminal part. The accessory cirrus is much smaller, colourless, situated at the 

 median side of the bristle-fascicle. The ventral cirrus, also colourless, is furnished with a short 

 basal part and reaches only to half the length of the bristle-fascicle. The anal cirri are two 

 club-shaped processes, composed of a conical basal joint and a globular terminal piece, that 

 has a dark hue. 



The bristles are vitreous; those of the dorsal fascicles with a pale greenish hue. The 

 dorsal as well as the ventral bristles are bifurcate, smooth, with a yellow tip; in the ventral 

 ones (PI. IX, fig. 3) the longer limb is faintly convex, whereas the short one measures about 

 a fifth of its length. The central canal of the shaft bifurcates at a short distance below the 

 fork. The dorsal bristles (PI. IX, fig. 1), that are somewhat more slender, have both limbs 

 nearly straight, situated next to each other, with a granular shagreen below the fork; their 

 central canal is not bifurcated but extends directly into the short limb, that measures about a 

 fourth of the long one. The anterior three segments contain only denticulated setae with a rather 

 divergent fork; they are usually triserrate in the first segment, bi- or uniserrate in the next 

 two (PI. IX, fig. 2). 



This worm could not be identified with one of the Notopygos-speóes hitherto described; 

 it is characterized not only by its great length, but also by the great number of its caruncle- 

 folds and the situation of the anal pore, that lies far backward. In Notopygos (Lirione) rayneri, 

 measuring about 56 mm. in length, the anus is situated on segment 22, in Notop. maculata 

 (20 mm. of length) in segment 23, whereas in Notop. variabilis, (55 mm. long), according to 

 Potts, it lies on segment 22 or 25; this statement however appears somewhat dubious to me 

 for in all the none Siboga-specimens the anal orifice constantly is situated on the same seg 

 ment (25*) and therefore it may be supposed, that in Notop. variabilis specimens are ranged 

 belongïng to two different species. In Notop. maculata the caruncle has a much smaller number 

 of folds, only 15, and in Notop. labiatus about 17, according to Malaquin and Dehorne 

 moreover in the last species it is straightly cut off at its posterior extremity. The Siboga-species 

 comes next to Potts' Notop. gardineri, but in this species the anus lies on segment 24, and 

 its caruncle is furnished with close-set folds, that are narrow and not grooved. 



ö 



2. Notopygos sibogae Horst. PI. IX, figs. 4 and 5. 



Horst, loc. cit. Vol. XXXIII, p. 245. 



Stat. 144. Anchorage north of Salomakiëe (Damar-)island. 1 specimen. 



Stat. 169. Anchorage off Atjatuning, West-coast of New-Guinea. 3 specimens. 



Stat. 193. Sanana-bay, East-coast of Sula Besi. Reef. 1 specimen. 



Stat. 234. Nalahia-bay, Nusa-Laut island. Reef. 2 specimens. 



A rather stout worm, though half as large as the foregoing one. The largest specimen 

 has a length of 35 mm., and a breadth of S 1 /, mm. (without bristles), whereas the number of 

 its segments amounts to 30. The smallest specimen measures only 21 mm. in length. The body 

 has an elongated oval shape, somewhat obtuse anteriorly, tapering posteriorly ; its lateral sides 

 are rectangular. On the dorsum of each segment there is an area, having the shape of a 



