POLYCH.ETA. BENHAM. 235 



Genus LYSARETE, Kinberg. 



LYSARETE AUSTRALIENSIS, sp. nov. 



(Plate xliii., figs. 103-109 ; Plate xliv., figs. 110-112.) 



An anterior fragment, consisting of the head and 70 chseti- 

 gerous segments of what is evidently a veiy large worm. It 

 measures 110mm. in length, with a breadth of 10mm. over 

 the body, and 14 over the parapodia ; the height is !> mm. 

 The peristomium is 6 mm. across, and the diameter thence 

 increases, till at the 10th segment it has attained its full 

 measure, which is retained for the remainder of the fragment. 

 The segments are l-5th the diameter of the body. 



The colour of the worm is a rich dark copper brown, with a 

 well marked green iridescence. 



The prostomium is a short rounded cone, slightly broader 

 than long ; its length is equal to that of the peristomium, 

 nuchal and first chsetigerous segments (PI. xliii., fig. 103). It 

 bears three short cylindrical tentacles, which arise in a curve ; 

 the median, which is inserted behind the others, is longer than 

 the admedian and is nearly as long as the peristomium and 

 nuchal segment. These tentacles lie backwards in a deep groove 

 excavated in the upper surface of the peristomium, nuchal 

 and first chyetigerous segments. It is broad in front, where 

 the overhanging margin of the peristomium is interrupted, 

 while the posterior region of this segment is excavated, and 

 this excavation is successively narrower in the two following 

 segments (PI. xliii., fig. 104). 



There are two pairs of eyes, both of very small size ; the 

 anterior are difficult to see owing to the deep pigmentation 

 of the skin of the prostomium ; they lie outside the bases of 

 the admedian tentacles. The second pair lie between the 

 median and admedian tentacles, anil can only be seen when 

 these are turned forwards. 



The surface of the first three segments is marked by 

 numerous short irregular longitudinal furrows. 



The under surface of the prostomium presents no groove, 

 but at the base, on each side, is a large prominent convex 

 lobe, triangular at its origin (PI. xliii., fig. 105). One apex is 

 directed backwards, the opposite side is forwards, a second 

 side faces inwards ; the third, backwards and outwards. 

 Between these palps and behind them are several transverse 

 folds, probably due to the partial eversion of the pharynx. 



