124 DISCOVERY REPORTS 



elongated, rectangular caruncle on each side of which the nuchal organs form a rounded 

 lobe. These nuchal lobes are connected by a narrow neck at the sides of the head with 

 paired semicircular nuchal processes lying at the outer and hinder angles of the caruncle. 

 This condition is somewhat like that in T. lohifera except that the nuchal organs do not 

 curve round in front of the caruncle. The everted proboscis is conical and about as long 

 as the head. 



The cirri (Fig. 17 b) in the mid-body have a very wide basal insertion. They are 

 broadly triangular and their whole surface is a mass of rounded sieve cells {cellules en 

 tamis) (Fig. 17 c). Towards the end of the body the cirri gradually lengthen out and 

 become narrowly lanceolate. The bristles begin on the 12th- 13th cirrigerous segment. 

 They are simple, acicular bristles usually two in number in each foot and are separated 

 by an aciculum, the point of which projects beyond the end of its sheath. At the end 

 of the body there is a sort of tail fan, consisting of a pair of elongate, oval, anal cirri, 

 each supported down the middle by a kind of hyaline process. 



Remarks. I have examined Benham's example from the Ross Sea, and although 

 it is small and rather ill-preserved I believe it to be conspecific with these specimens. 

 Gravier and Benham, working on poor material, have both in my opinion failed to 

 interpret the structure of the nuchal organs and did not see the connection between the 

 lateral and posterior nuchal lobes. The nuchal organs and caruncle in the present species 

 are more those of a Travisiopsisthan of a Sagitella. I have compared these specimens with 

 an example of Wagner's S. kowaleivskii from Madeira, and in my opinion it is a different 

 species. The structure of the nuchal organs with the narrow connection between the 

 anterior and posterior lobes is unlike that of any other Travisiopsis . 



Family SYLLIDAE 



1. No ventral cirri Autolytus 



With ventral cirri... ... ... ... ... ... ... ... ... ... ... 2 



2. Dorsal cirri moniliform. Palps separate ... ... ... ... ... ... ... 3 



Dorsal cirri unsegmented. Palps fused at their base 4 



3 . Body long, flat and ribbon-like ... ... ... ... Trypanosyllis 



Body short and subcylindrical ... Syllis 



4. Rim of pharynx smooth ... ... ... ... Pionosyllis 



Rim of pharynx denticulated ... ... ... 5 



5. With a coiled pharynx. Nuchal epaulettes present Amblyosyllis 



Pharynx straight. No nuchal epaulettes Eusyllis 



Genus Syllis, Savigny 

 The palps are separate, not fused. The tentacles and dorsal cirri are moniliform. 

 There is a single anterior pharyngeal tooth and the pharynx has a crown of soft papillae. 

 The bristles are compound, with heterogomph unidentate or bidentate blades. 



1. Bristles unidentate Syllis prolixa 



Bristles bidentate ... ... ... ... ... ... ... ... ... ... 2 



2. Articulation between chaetal blade and shaft obscure. Dorsal cirri long and slender 



S. sderolaema 

 Articulation between chaetal blade and shaft obvious. Dorsal cirri short and spindle-shaped 



S. brachychaeta 



