74 ZOOLOGISCHE MEDEDEELINGEN — DEEL IL 



Laetmonice-sipecies, closely allied to Laetm. filicornis. The largest of them 

 has a length of 40 mm., but usually they are not longer than 32 mm.; 

 the number of segments amounts to 34. They are especially characterised 

 by their large dorsal spines, the shaft of which is provided on 

 one side with several series of distinct thorns; these bristles 

 are stout, dark brown, in the anterior segments reaching to the median 

 body-region, whereas those of the middle of the body extend beyond the 

 anal extremity. Their distal end is provided with three small, trigonal, 

 alternating fangs. The ventral bristles are provided with a dense series 

 of fine, slender pinnae, separated at its base by a short interval, from the 

 distal hook, that is not very long, hardly a third of the length of the 

 pinnae. No dorsal felt occurs. There are 15 pairs of elytra, usually not 

 overlapping each other and covering the whole dorsum, or leaving the 

 middle of it bare ; the ventral side of the body is smooth, not beset with 

 papillae as in Laetm, filicornis, whereas its median region is thin, translucent. 



Laetmonice rugosa n. sp. 



Siboga-expedition, Stat. 302, north off Rotti-island. 



The largest of the specimens has a length of 32 mm. ; the number of 

 its segments amounts to 34. The dorsum of the body is covered by a 

 felt, while its ventral side has a rugose appearance, due to the presence 

 of closely packed globular papillae; its median region is not 

 translucent as in the preceding species. The stout dorsal bristles are golden- 

 yellow, half as long as the body, with three alternating, pointed fangs 

 beneath the hastate tip ; their shaft shows a row of tubercles along one 

 side. The short dorsal bristles are densely covered with small tubercles. 

 The ventral bristles are not pinnate, but provided with four 

 or five large spines; in this character the species agrees with 

 Hermione. 



Laetmonice dubiosa n. sp. 



Siboga-expedition, Stat. 302, north off Rotti-island. 



Besides the specimens of Laetm. rugosa at Stat. 302 another worm 

 of the same genus was collected, that could not be identified with any 

 known species. It measures 28 mm. in length, whereas the number of 

 its segments amounts to 35. It is especially characterised by the shape 

 of its large dorsal bristles; these are golden-yellow, with a smooth, 

 flat and rather broad shaft, that beneath the barbed tip is sud- 

 denly constricted. The tip is provided with three pairs of alter- 

 nating, elongated, curved fangs. The bristles extend posteriorly over 10 

 to 12 succeeding segments. The ventral bristles have the usual shape and 



