274 CEYLON PEAEL OYSTER REPORT. 



fig. 92). The appendix of a superior ventral falciger in this foot is fringed along its 

 lower portion, guarded along its upper half (Plate IV., fig. 93). The appendices of 

 the other ventral falcigers of this foot and of the other feet, and also in many other 

 species of Nereidae, are minutely guarded quite at the apex beyond the fringe ; a 

 double contour at this point indicates a rudimentary guard, as may be realised by 

 comparison with the structure of the superior ventral setae here described (Plate IV., 

 fig. 93). 



The parapodium (44th) from the middle region of the body described above closely 

 resembles that figured by Gravier for his Platynereis insolita (' Arch. Mus. Paris ' 

 (4), iii., 1901, p. 198), and, in fact, could not be distinguished from it. The only 

 difference seems to lie in the structure of the appendices of the dorsal falcigerous setae 

 which have a smooth rounded vertex without any prominence in P. insolita (loc. cit., 

 p. 198, fig. 20G). The same setae with tooth on the vertex occur also, two in number, 

 in the 1 9th foot of the Ceylon specimen. 



The tentacular cirri are long, the third pair extending over 16 segments. The 

 proboscis was retracted and had to be dissected out : Paragnaths of the orders L, II., 

 III., and V. absent; of the order IV. (Plate IV., fig. 94) in several more or less 

 complete rows (as in the type). Antennae as long as the palps, eyes in a trapezium. 



Family: ONUPHID^. 



Diopatra amboinensis, Aud. & M.-Edw. Plate IV, figs. 95 to 97. 



Station V., off Chilaw Paar, 11 fathoms. One specimen with tube. 



Another empty tube was taken from the Muttuvaratu Paar, 29th March, 1902. 



The tube is characteristic, encrusted with unequal pieces of coarse broken shells 

 which stand out at right angles to the wall of the tube, being attached thereto by 

 one edge, giving the impression of pieces of shell threaded together ; some of the 

 fragments are nearly entire shells, as much as f inch long, the majority are smaller ; 

 seaweed may grow on the shelly covering ; the tube is from 3 to 3|- inches long, and 

 presents a tabulate appearance owing to the disposition described above. 



The body of the specimen, which is incomplete behind, is flattened, 4 millims. 

 wide. The dorsal side is brown coloured, with a dark haemal line and a shining 

 cuticle ; the lateral parapodial tracts show up whitish in the preserved state ; 

 ventrally there is a pale neural tract flanked by two broad brown submedian bands, 

 followed on the outside by the series of broad whitish ventro-lateral tori or cushions 

 which resemble the uncinigerous tori of a Terebellid without the uncini, and doubt- 

 less serve to facilitate the passage of the worm up and down its tube. The first five 

 setigers are much larger than the rest, with a ventral and pc-rrect inclination, and 

 carry ventral cirri instead of tori. The spiral penicillate branchiae commence on the 

 sixth segment (i.e., fifth setigerous segment). Towards the fortieth segment they 

 become reduced and finally cease in the region of the sixtieth ; in the mid-region 

 they are more than twice the length of the stout, subulate dorsal cirri. 



