3^ 



longest towards the tip of the organ. The dorsal division forms 

 a separate elevation with the spine-papilla (pierced by the spine) 

 at its outer and lower border. It carries a group of transparent 

 slightly curved spinous bristles {Plate II., tig. 2, one of 

 the shorter), which Schmarda figures as bilid terminally, and, 

 which at first sight have this appearance, but the condition 

 is only apparent, as more careful examination shows that 

 the tips have been fractured, and, that in many, the split 

 parts give a pseudo-bifid aspect. The shorter forms at the 

 inner border of the fan, which have been shielded by the 

 longer, have simple tips tapering to a point. The latter is often 

 coated with a finely granular investment. These bristles are 

 more slender and elongate posteriorly. They are evidently 

 brittle, and, if the species, like Polyiioe scolopcndrina, inhabited 

 a tube, and was commensal, the fracture of the tips would he 

 explained. 



The mass of the foot is formed by the ventral division, and 

 the great yellow spine is more powerful than the superior, 

 whilst its papilla is posterior. In front, another and longer 

 conical papilla projects outward. The first or upper bristle is 

 much stronger than the others, of a deep yellow colour, and 

 hastate (Plate II., fig. 3, from the 40th foot), yet there are 

 indications that it is only a modified form of the series which 

 follows, for traces of rows of spines are present — especially in 

 the anterior and posterior parts of the body, and even the tip 

 occasionally shows a minute spike, or secondary process. At 

 the loth foot, for instance (Plate II., fig. 4), it is only a some- 

 what larger bristle, with a long spinous simple tip. At the 30th 

 and 40th feet, on the other hand, it is truly hastate or javelin- 

 shaped, and nearly symmetrical, yet a trace of the spinous 

 rows occurs on the left. These are barely visible at the 50th 

 foot, but, again re-appear in the bristles of the caudal region. 

 All the bristles below the larger conform to the same type, 

 having straight translucent and slightly yellowish shafts, the 

 terminal region being enlarged ^t its commencement, dimin- 

 ishing distally till it reaches the bifid tip, where a slight 

 dilatation again occurs (Plate II., fig. 5). Rows of spikes 

 appear on the upper edge of the tip. These bristles have longer 

 tips in the loth foot, and they diminish in length and increase 

 in strength for some distance backward, and remain short in 

 the caudal region. 



The ventral cirrus is short and subulate, the tip reaching 

 only a little beyond the bases of the nearest bristles. Its 

 surface, with the exception of the filiform tip, has clavate papillae. 



In all probability, the habit of this species is akin to that of 

 such forms as Polvnoc scolopeiidriiw, being a commensal with 

 another Annelid, mollusc or echinuderm. It is doubtful, if 



