I07 



fühler sehr kurz sei, dass zwei Antennen ('unsere F Li h Ie r\v i m p e r p ols t er) vorhanden . . . ", 

 whereas the lateral antennae of Thalciiessa have nothing to do with antennal ctenidia. 

 The genera of Sigalioniiiae ma)- be easil)- recognized b)- the following key : 



Median antenna (tentacle) 



absent Sigalion Aud. et M. Edw. 



Lateral antennae inserted upon the prostomium Enilialenessa Darb. 



,T , ( appendix mono- 



Neuropod. | ' ^ 



setae with 



cheliforni 



appendix 



pr< 



. Lateral antennae 

 ;nt ! 



fused with the 

 buccal segment 



Ctenidia 

 present 



I and multi- 

 articulate 

 appendix only 

 multi-articulate 

 iieuropod. setae with 

 pectin. canaliculate appendix 

 neuropod. setae with 



knife-like appendix Eiileanira Horst. 



Ctenidia absent Psammolvce Kinb. 



Sthenelais Kinb. 

 Eustlienelais Mc Int. 

 Leanira Kinb. 



Genus Euthalenessa Darboux '). 



(2'halenessa Mc. Intosh-) 



Prostomium with three small antennae and four large eyes. A dorsal cirrus on the third 

 segment. Elytra generally with ramose papillae on the margin. Parapodia with ctenidia on the 

 dorsum and stylodes at the tip. Dorsal bristles slender, with spiral, denticulate whorls ; ventral 

 bristles, with cheliform, simple or multi-articulate appendix. 



The genus Thalenessa was established by Baird in 1868 for Sigalion Edwardsi Kinb., 

 a species that how^ever has been proved to belong in fact to the genus Sigalion^ because the 

 tentacle is absent. It was therefore at variance with the rules of nomenclature, that Mc Intosh 

 afterwards gave that name to a group of Sigalionidae, with a short tentacle. Consequently 

 Darboux rightly proposed to use in stead of Thalenessa the name of Euthalenessa, as also 

 has been approved by M.\renzeller (Polychaten des Grundes, 1902, p. 8) and Ehlers (Die 

 bodensassigen Anneliden, p. 52). 



I. } Enthalenessa oculata (Mc Int.). PI. XXII, figs. i — 3. 

 [Thalenessa oculata Mc Int.). 



Mc Intosh, loc. cit., p. 142, PI. XXI, figs. i, 2; PI. XXIII, fig. 12; PI. XXV, fig. 3; PI. 



XIII A, figs. II and 12. 

 IZUKA, loc. cit., p. 86, pi. X, figs. I and 2. 



Stat. 37. Sailus Ketjil, Paternoster Islands. Depth 27 M. and less. i specimen. 

 Stat. 60. Haingsisi, Samau Island. Shore-exploration. 3 specimens. 



Stat. 99. 6° 7.5 Lat. N., I20°26' Long. E. Anchorage off North Ubian. Depth_ 16— 23 M. i 

 incomplete specimen. 



1) Loc. cit. p. 79. \ 



2) Loc. cit. p. 139. 



63 



