EUNICIDAE 151 



The pseudo-compound crochets of the first four chaetigers are tridentate. A pair of 

 hooded bidentate subchaetal spines appear at about the 15th foot. 



The dental formula is approximately 8-8:9 + 5-7. The carriers taper down to 

 fine points. 



Remarks. Without seeing Johnson's type I cannot be certain that these specimens 

 belong to his species, but as far as his description goes I can find nothing to keep them 

 apart. 



Onuphis dorsalis (Ehlers). 



Diopatra dorsalis, Ehlers, 1897, p. 71, pi. v, figs. 108-118. 

 Onuphis quadriciispis, Monro, 1930, p. 131, fig. 49 a-c. 

 Onuphis dorsalis, Augener, 1931, p. 294. 



Occurrence. St. WS 212 (2); WS 764 (2); WS 771 (3); WS 772 (12); WS 774 (5); WS 783 (2); 

 WS 786 (4); WS 808 (7); WS 863 (i). 



Specific characters. Almost the only complete specimen measures 48 mm. by 

 2 mm. at the widest part for no chaetigers. The first five chaetigers are usually only 

 slightly pigmented on the dorsum, the intensity of the pigment increasing from before 

 backwards, but from about the 6th to the 25th chaetiger there are deep reddish brown 

 transverse bands across the back. Behind this the pigment fades out rather rapidly. 

 The first four or five chaetigers form a kind of neck, the segments being narrow and 

 cylindrical and i^ times as long as a segment from the middle of the body. The ventral 

 cirrus is converted into a pad by the 6th-7th chaetiger. The cirriform posterior lip of 

 the chaeta-sac disappears about the 17th foot. The branchiae begin at the 6th chaetiger 

 and about the last 45 chaetigers of the body are abranchiate. The number of filaments 

 is variable. Usually there are only two filaments, the second filament appearing early 

 in the branchiate region and disappearing at about the 40th chaetiger, but in a few 

 specimens a third filament is developed at about the 30th chaetiger. And again in some 

 of the smaller examples a second filament is not developed and the gills remain single 

 throughout. The fully developed gill is longer than the dorsal cirrus. 



The first five chaetigers have capillary bristles and pseudo-compound bristles; the 

 arrangement of the latter is somewhat variable, but the most usual condition is for the 

 first three chaetigers to carry perfectly smooth pseudo-compound bristles without teeth 

 and apparently without hoods, as figured by me {loc. cit., fig. 49 b). The 4th and 5th 

 chaetigers carry in addition bidentate and tridentate pseudo-compound bristles. The 

 comb-chaetae have about 12 rather long narrow teeth. At about the 15th chaetiger a 

 pair of bidentate hooded subacicular hooks appear. The feet are supported by three 

 rather slender yellow pointed acicula. 



Ehlers figures the jaws. The dental formula is approximately 8 — 8:7 + 9 — 12. 

 M. V is represented by two small chitinous plates. 



Remarks. In 1930 I attributed several specimens of this species to O. quadriciispis, 

 Sars, and I still think it very doubtful that O. dorsalis is more than a coloured form of 

 Sars' species. Unfortunately the material of O. quadriciispis in the Museum collection 



