242 RKC0RDS OF 111 K AUSTRALIAN MUSEUM. 



the frontal ridge, broad above but keel-like between the palps. 

 This ridge ends ventrally in front of the mouth, a transverse 

 aperture on the peristomium. Behind the mouth is the longitu- 

 dinally ridged lip. The parapodia of this segment are shifted 

 forwards and lie in front of the mouth, just external to the bases 

 of the palps. 



Each palp is fairly long, measuring nine mm. in the type (PI. 

 lxix., tig. 1), i.e., less than one eighth of the length of the 

 animal. \n a eo-type figured on PI. lxix., fig. 2, they are relatively 

 shorter. Mcintosh does not mention their length in A. australis 

 but the figures show them to be relatively longer, being more 

 than one-fifth of the body-length. In our specimens they are 

 rounded and tapering, the base of each showing a swollen pari 

 just laterally to the tentacle. The surface of the palp, except 

 at the distal end, is beset with very small chitinous papillae, the 

 extremity of each being tine, sharp and bent towards the tip of 

 the organ (PI. lxix., tig, 4.) 



As in other Aphroditidse, there are several sets of bristles ; the 

 strong laterally-situated setae, the so-called "hairs" and dorsal 

 "felt." The felt consists of very closely matted delicate seta 1 , 

 forming a tough, dense mass, in which mud becomes entangled, 

 giving a dirty grey appearance to it. The elytra are completely 

 concealed by it. Iridescent setse are very numerous along the sides 

 of the animal. They are long, jointed, highly flexible and hairlike, 

 and taper to a tine point. They arise from the lower part of the 

 dorsal division of the foot (notopodium). These "hairs" are respon- 

 sible for the beautiful colours characteristic of a " Sea-mouse." A 

 pale bluish green hue predominates, but it merges into red, 

 orange, and yellow. The colour is scarcely noticeable in very 

 young specimens but increases with the size of the worm. The 

 dorsal seta? are rather stitf. They arise from the upper part of 

 the notopodium, but curve upwards and inwards, penetrate the 

 dorsal felt, and come to lie over the dorsum, those from oppo- 

 site sides almost meeting in most cases, and actually overlapping 

 in places. They taper gradually and end in a delicate hook 

 (PI. lxix., tig. 2), similar to that figured for Lcetmatonice aphro- 

 ditoides, Mclnt., 8 and Aphrodita aculeata, Linn. 4 Longitudinal 

 and transverse striatums are fairly well marked. Their structure 

 is thus quite different to those in A. australis, as figured. The 

 bristles which project from the sides of the animal closely 

 resemble in position and shape those of A. aculeata. They are 



■'• Mel ' t<>s)i Loc. > >>.. ]>■ 51. 



* Mcintosh -Mon. Hi it. Annelida, Pt. ii. (Ray Soc, 1900, p. 247). 



