SYSTEMATIC ACCOUNT 



191 



Genus Rhynchonerella Costa, 1862 

 (Emended Claparede, 1868, pro Rhynchonereella Costa, 1862) 

 Prostomium extending beyond the eyes and carrying five antennae. Five pairs of tentacular cirri. 

 Parapodia with a cirriform appendage on the pedal lobe ; with simple and/or compound chaetae. 

 Type species. Rhynchonerella gracilis Costa, 1862. 

 Type locality. Gulf of Naples. 



Rhynchonerella bongraini (Gravier), 191 1, n.comb. 

 Type locality. Pelagic haul off the Ice Edge, 69 1 5' S., 108 5' W., brought from 950 m. to the surface. 



Callizona Bongraini Gravier, 1911a, p. 312. 



Callizona Bongraini Gravier, 191 16, p. 70, pi. 4, figs. 39-43. 



Callizona Bongraini Gravier, 1911c, p. 694. 



Callizonella bongraini Augener, 1929, pp. 294-300, fig. 2a-g. 



Callizona bongraini Benham, 1929, pp. 189-90, pi. 1, figs. 11-12. 



Rhynchonerella fulgens Monro, 1930, p. 83, fig. 26. 



Alciopid larvae Hardy and Gunther, 1935, p. 117. 



Callizonella Bongraini Fauvel, 1936a, pp. 18-19. 



Callizonella bongraini Monro, 1936, p. 119. 



Krohnia Bongraini Stop-Bowitz, 1948, p. 33. 



Krohnia Bongraini Stop-Bowitz, 1949, pp. 9-12, figs. 3-4. 



Krohnia Bongraini Stop-Bowitz, 195 1, p. 8. 



Description. The majority of specimens are not complete, except one which measures 13 mm. in 

 length for fifty-one chaetigers with a width across the tips of chaetae of 3-5 mm. Of the incomplete 

 specimens one measures 15 mm. long for fifty-nine chaetigers, and \ 



another 1 1 mm. for forty chaetigers. There are two pairs of short, 

 foliaceous antennae set close together on the anterior border of 

 the prostomium and a median, single, subulate antenna set in the 

 middle of the dorsal surface in the groove between the two enormous 

 spherical eyes. These eyes have a diameter of approximately 0-3 mm. 

 each and cover about 90% of the prostomial surface. The five pairs 



of tentacular cirri are arranged thus 



1 -) 1-- ; the unpaired anterior 



is medium in length, the dorsal pair long (posterior longest, about 

 0-5 mm.), and the ventral pair short. Parapodia have large foliaceous 

 dorsal cirri and smaller ventral foliaceous cirri ; the cirriform append- 

 age on the pedal lobe is very small. Characteristic compound chaetae 

 with smooth or denticulated terminal articles (Text-fig. 1 2 a-b) appear 

 on the first seven or eight chaetigers. The chaetae with smooth 

 articles are two to three times longer than the others but not so 

 numerous. On the last two feet carrying compound chaetae, very 

 much longer simple chaetae appear and gradually replace the former 

 completely. Aciculae appear on all feet. Segmental glands are present, 

 but rarely before the tenth foot; they are seldom pigmented. The 

 proboscis is terminated by twelve blunt papillae. 



Discussion. No one has ever reported specimens of the species originally described as Callizona 

 bongraini without compound chaetae on the anterior feet. Stop-Bowitz (1948, 1949 and 1951), however, 



(a) ' (b) 



Text-fig. 12. Rhynchonerella bongraini: 

 compound chaetae with (a) smooth 

 terminal articles, (b) denticulate ter- 

 minal articles. 



