POLYCH^ETA BENHAM. 59 



The dorsal surface of the head and neck is pale brown; the rest of the body is of 

 the same tint, with darker brown markings at the base of each parapod, both above and 

 below; at irregular intervals along the body this deeper tint extends further over the 

 surface, both dorsally and ventrally, forming larger and smaller areas, which nearly 

 meet on the dorsal surface. 



The male is imperfect, consisting of head and 56 segments, with a length of 

 65 mm. As Gravier has pointed out, the glands below the parapods are much better 

 developed than in the female, and I note a series of segmental white marks along the 

 median ventral line which are better developed in the hinder part of the fragment than 

 anteriorly. These are not present in the female. 



The anatomy of the worm agrees both with the account given by Willey and 

 the more complete one by Gravier, except that the latter states that the colour of the 

 specimens gathered by the French expedition, when alive was " vert jaunatre," and 

 that the spots were " vert epinard fonce." 



There is, however, one important difference between these two accounts. Willey 

 found, contrary to Mclntosh's statement, that the bristles are " articulated," though 

 he found it difficult to detect the articulations, till the bunch of chaetse was " sp ead 

 out." Gravier, on the other hand, insists that they are " entire," and consequently 

 expresses doubts as to the identity of Willey's specimens with that described by 

 Mclntosh and by himself. He enumerates three points of difference namely, (1) in 

 regard to the chaetae; (2) in regard to the absence in Willey's account of any description 

 of the dorsal surface of the head; and (3), in regard to the papillae at the entrance to the 

 pharynx. 



I will offer remarks on each of these points, and hope to clear up the doubts 

 expressed by him. 



(1) For some time I was unable to detect any articulation in the chaetse. I 

 followed Willey's advice to " spread them out," but failed at first to see any sign of 

 ]omting, even under high power. But chancing to shift the mirror of the microscope 

 so that the light was no longer fully reflected, I noted an extremely faint and very 

 oblique line crossing the very delicate and transparent bristles. This " jointing " is so 

 unlike what one would expect from Willey's figure, the reproduction of which is coarse; 

 it is so unlike the articulation that occurs, for instance, in Halodora, that it is easily 

 overlooked. When viewed from the side the articulation, if one may call it so, has the 

 appearance of a very oblique interruption in the chaetal substance, which does not 

 seem to reach the edges in all cases; but most of the appendices have the appearance 

 of being " spliced " to the shaft, that is, it and the shaft are obliquely cut across 

 (fig. 62). Occasionally, one finds a chaeta lying in a different plane, and the splicing 

 appears to be more perfect and definite, where the distal appendix has its base sliced 

 off on both sides to a point, and this fits into a V-shaped cut at the end of the shaft 

 (fig. 63). ... 



