io6 



structure, having half its surface covered with small conical tubercles. The neuropodial branch 

 of the parapodia is triangular, with u cyhndrical lobe at its tip. lts bristles, of the usual struc- 

 ture, are faintly bifid, with a rudimentary secondary process ; the dorsal setae (PI. XXI, fig. 20) 

 terminating in a bkmt tooth, whereas the ventral ones have an acute curved tip. The rounded 

 notopodial branch also has a conical lobe, enclosing the acicula ; its bristles are slightly bent, 

 and have the usual appearance. The ventral cirrus is dilated in its basal part, tapering dis- 

 tally, nearly as long as the neuropodial branch. 



Sub-family Sig.\lionin.\e. 



Body elongate and narrow. Proboscis with "/g. "/ii °'' "As papillae and four teeth. Gene- 

 rally three antennae; the lateral ones inserted on the anterior margin of the prostomium or 

 fused with the first parapodia. Eyes sessile, two or four. Elytra on the segments 2, 4, 5, 7 — 

 25, 27, 28 and the succeeding ones; generally a branchial appendix on all the segments be- 

 hind the third one. Ctenidia often present on the parapodia and the prostomium. Dorsal bristles 

 simple, spinous and tapering ; ventral bristles compound, their terminal appendix being often 

 long, multi-articulate and bifid. Two long anal cirri. 



Though our knowledge of the Sigalioninae much increasëd in the last years thanks to 

 the arduous investigations of Mc Intosh, Pruvot et Racovitza, Darboux, Willey a. o., yet 

 there still reigns a good deal of confusion about the exact diagnosis of the genera. Sthenelais 

 simplex Ehl.^) f. i. has rightly been ranged by Augener") among the genus Leanira ; Leanira 

 Giardi Darb. ^), according to the investigations of Marenzeller, belongs to Sthenelais^) and 

 Thalenessa stylolepis Willey^) will prove, as I presume, to be a species of Sigalion. This 

 may partly be ascribed to the circumstance, that only a few of the investigators could dispose of a 

 large material and therefore were obliged to borrow their knowledge from the often inadequate 

 descriptions of others ; but it may also have been caused thereby, that there was no agree- 

 ment about the characters, that offer a thrustworthy criterion for the distinction of the genera. 

 Marenzeller however in his critical account of the genus Leanira^), has given us a clear 

 review of the various often inexact ideas of the authors reofardingr this matter and stated, that 

 besides the presence or absence of the tentacle (median antenna) and the situation of the 

 lateral antennae (on the prostomium or on the buccal segment), the structure of the ventral 

 bristles furnish "das ausschlaggebende Moment" to distinguish the different genera. Unfortuna- 

 tely a "lapsus calami" has crept into his account; for he says "ausserdem charakterisirt 

 Mc Intosh seine Gattung {Thalenessa) noch durch die Bemerkung, dass der unpaare Stirn- 



1) Eiu.EKS, Florida-Anndiden, 18S7, p. 60, PI. XIII, tïgs. 2, 3, PI. XIV, figs. 1—6. 



2) West-Indische Polychaeten, p. 106. 



3) Loc. cit. p. 123. 



4) V. Marenzeller, Polychaten des Gvundei. 1902, p. 7: Fauvei., Folychètes de l'Hirondelle et de la Priocesse-Alice. 

 1913, p. 30. 



5) Loc. cit. p, 261. 



6^ Polychaten des Gitindes, p. 8. 



62 



