128 



DISCOVERY REPORTS 



5 MM 



Fig. 20. Pionosyllis comosa. 

 Head from above. 



Pionosyllis comosa, Gravier (Fig. 20). 



Gravier, 1907, p. 15, pi. ii, figs. 12-13. 

 Benham, 1921, p. 22. 



Occurrence. St. 929, New Zealand (4). 



Specific characters. I have some hesitation in attributing these New Zealand 

 specimens to Gravier's Antarctic species. They are all fragmentary and the largest 

 measures 24 mm. by 2 mm. for 43 chaetigers. 

 The body is dorsally arched, and in spirit there 

 are no colour-markings. The head (Fig. 20) is 

 about 1 1 times as long as broad. It is produced 

 backwards into two long lobes divided by a deep 

 median cleft, and behind the head there is a 

 low nuchal collar. There are two pairs of orange- 

 coloured eyes. The palps are fused at their base 

 and the median tentacle is about three times as 

 long as the head. The laterals are about two- 

 thirds of this. There are two pairs of tentacular 

 cirri In the anterior region the dorsal cirri are 

 very long, being equal to the length of about 

 12 segments in the front region. Over the rest 

 of the body they are rather longer than the 



body is broad. The pharynx extends to the 13th chaetiger and the proventriculus to 

 the 22nd. There is a single anterior tooth and the mouth of the pharynx appears to be 

 quite smooth; there is a circle of papillae around the pharyngeal rim. 



The feet are rounded in outline and are supported by three curious acicula with blunt 

 tips that are curved at the end. The bristles have stout denticulated and bidentate end- 

 pieces, longer in the upper part of the foot than in the lower. The ventral cirri are rather 

 stout, more or less conical structures, about as long as the feet. 



One of the specimens is an epitocous female with swimming bristles beginning at the 

 19th chaetiger. The posterior region in all these examples is lacking, and I have seen no 

 simple bristles. 



Remarks. I have compared these specimens with an example from South Georgia, 

 and except for the great backward prolongation of the head I can find no ground for 

 separation. 



The shape of the head may be, to some extent at least, the result of post-mortem 

 distortion. Moreover, Ehlers has attributed to this species some specimens in which 

 the posterior cleft of the head is apparently entirely absent (Ehlers, 1913, p. 473). From 

 this it would appear that the shape of the head, at any rate in preserved specimens, is 

 subject to considerable variation. 



Pionosyllis nutrix, n.sp. (Fig. 21 a-d). 

 Occurrence. St. WS 564 (12). 



