354 PART II. SYSTEMATIC ACCOUNT 



H. gracilis is the closest in general appearance to H. talboti, but, in addition 

 to differences in size and the number of tentacles, they differ in the size of the 

 adhesive plates which are 1 5 to 20/x long in H. gracilis and 30 to 40/x long in 

 H. talboti. Examination of more specimens of H. talboti might disclose more 

 differences, since all four of Ivanov's species have, on part of the preannular 

 metasoma, an area or row of large papillae set close together, whose arrange- 

 ment and number varies with the species. In H. talboti some large papillae 

 are visible in the correct region but their arrangement cannot be seen clearly. 

 Another useful specific character in this genus is the arrangement of the 

 papillae on the postannular region, which has been lost by the present 

 specimen. 



Material : one occupied tube (holotype) and twelve empty fragments. 



Locality: West coast of S. Africa, 33°26'S, 16°33'E, 33°50'S, 17°21'E, 

 33°50'S, 16°30'E. 



Depth: 1097-2890 m. — E.C.S.] 



[6. Heptabrachia celebensis (Southward) (Fig. D144) 

 Southward, 1961b: 15-16, 21, Fig. 9 {Polybrachia celebensis). 



This species forms part of the Siboga material, originally included in 

 Siboglinum weberi. The following description is transcribed from Southward 

 (1961), by kind permission of the author and the publisher, E. J. Brill. This 

 species must be ascribed to the genus Heptabrachia because of the small 

 number of tentacles, the presence of a pretentacular groove, the presence of 

 a secondary groove on the mesosoma and because of the general character 

 of the tube. 



"Two fairly complete animals are available, 21 and 35 mm long; one has 

 four tentacles, 8-5 mm long, and the other has six shorter ones. In the latter 

 the tentacles seem to be attached in two groups of three (Fig. D144G) but 

 in the former the arrangement of the tentacles is not at all clear. There is a 

 band of pinnules on each tentacle, apparently three or four pinnules wide; 

 each pinnule is about 0-1 mm long, which is the same as the diameter of the 

 tentacle. The fore-part of the body is contracted in one specimen (Fig. 

 D144A E, F) and extended in the other (Fig. D144G) and the total lengths 

 of the protosoma and mesosoma in the two specimens are 0-78 and 1-5 mm 

 respectively. In both, the cephalic lobe is rather short and somewhat spoon- 

 shaped (Fig. D144i% G). A shallow annular groove between the protosoma 

 and mesosoma is followed by a second annular groove just in front of 



