1904.] POLYCH.ETA OF THE MALDIVE ARCHIPELAGO. 279 



abnormally, four. Their shape is shown in PL XVIII. fig. 4, the 

 end being slightly hollowed out between the two points. The 

 setse of this region vary considerably in form and strength. The 

 figure (PI. XVIII. fig. 5) shows the shapes found in the fifth and 

 in the last feet of this region. The majority are like " a," but in 

 the fifth foot are found dorsally a few of a more slender kind {b). 

 In the last foot most of the setas are more slender (c), and some 

 have narrow and slightly bent heads (d). 



The region B consists of two * segments, both of which bear 

 the usual type of " gill," which are here proportionately small, 

 directed horizontally and outwards, and flattened against the dorsal 

 surface of the body (PI. XVIII. fig. 6, not.). Each gill consists of 

 a dorsal part, bifid at the tip, and a more laterally placed mem- 

 branous triangular flap (PI. XVIII. fig. 6, gill). The median half 

 of the bifid notopodium contains about 40 capillary setse which do 

 not project, this large number being unusual in the genus. The 

 whole gill is delicately membranous, and white in colour, in 

 contrast to the darker (in spirit) glandular and muscular portions 

 of the body. The neuropodial tori are very large and muscular 

 (PI. XVIII. fig. 6, neur.d.), and only in the case of the left neuro- 

 podium of the second segment does its characteristic division into 

 a dorsal and a ventral part occxir. In this case the two parts 

 lie directly one above the other, as also throughout the region C 

 (PI. XVIII. fig. 6, neur.d. & neur.v.) ; of. also P. gardineri 

 (PI. XIX. fig. 5) and the other species of the genus. 



In all the species of this genus the anterior part of the body is 

 very glandular, but not usually conspicuously so beyond the limits 

 of the region A. In this species, however, we have (1) glandular 

 ridges in front of the first giUs (PI. XVIII. fig. 6, gl.) ; (2) from 

 the centre of each semicircular neuropodial torus springs a long 

 glandular cirrus which arches over the back. The second segment 

 appears to be without these glandular appendages, which are, I 

 believe, unique in the genus. 



Of the region only twelve segments are present, bvit probably 

 they are very numerous, as in F. majoi'. In all the species of 

 this gen^is this region is muscular only on the ventral surface. 

 Dorsally there is but a very delicate membrane between the large 

 cavity of the gut and the exterior, the region being thus of a dense 

 black colour dorsally and laterally, in consequence of the pigmen- 

 tation of the gut-walls. This very fragile dorsal surface is usually 

 ringed by narrow bands of muscle at each pair of parapodia, but 

 ill this species these muscles are scarcely visible externally. The 

 very small notopodia are conical, and contain about nine long, 

 bent setas (text-fig. 41, p. 280), the leaf-like ends of which project 



* As in P. major Clap, perhaps a third, gill-less, segment should he rectoned as 

 belonging to this region, hut whether Claparfede's contentions in favour of so doing 

 apply to P. aoiculigerus I am unable to say, the worm being broken at this point. 

 The matter is of vei-y small importance in any case, the parapodia of this third 

 segment being like those of the region C in both &pecie&. 



