14 THE VOYAGE OF H.M.S. CHALLENGER, 



(j)), and the suckers (s), appear like raised plates fastened to the ventral surface. The 

 contour of the parapodial plates is heart-shaped, and from their externally directed notch 

 springs the cyhndrieal, terminal joint of the parapodium. Its origin is marked by a 

 small swelling in the middle of the plate. The suckers are remarkably large. They 

 also look like round, raised plates between the parapodia ; but instead of the usual 

 hole in the centre, there is only a slight, annular depression surrounding a small, 

 central boss. The size and form of these suckers suggest that a careful investigation 

 would yield some answer to the cpestions raised by Nansen in regard to the function 

 and morphological import of these organs. 



The mouth is situated below the anterior margin of the first ventral ridge, and in 

 the specimen before me the anterior end of the pharynx (ph) is adorned with a circlet 

 of delicate papillae, 0"15 mm. in length. The cloaca seems to open close beside the 

 posterior end. 



Outside the third pair of parapodia lie the large male genital papillse ( ? ). Thej' 

 are more strongly developed than in any other species, and exhibit a retort-Like form. 

 Their free tubular termination seems to be movable, since it is bent on either side in 

 different directions, on the right side backwards, on the left forwards. The ventral 

 surface unoccupied by the above organs appears to be finely canaliculated, which is 

 probably an expression of the closely packed, radiating, intestinal branches. The dorsal 

 surface examined under the lens does not exhibit any particular sculpturing. 



The thickness of the body-disc is very considerable, and in the middle must measure 

 almost 1 mm., gradually decreasing, however, towards the blunt margin, but without 

 exhibiting any trace of a marginal fringe. On the other hand, the margin exhibits ten 

 pairs of fine cirri, of which the first pair, distinctly represented in fig. 1 1 (c), attain 

 a length of 0'58 mm. 



The total length of the body in its elongated state must have been almost 6 mm. ; 

 the maximum breadth of the single specimen before me is 5 mm. The colour, above 

 and below, is a uniform greyish -yellow. 



