i6o DISCOVERY REPORTS 



Genus Haploscoloplos, Monro 

 As Scoloplos, except that there are no hooks in the thoracic region and an inter- 

 mediate cirrus may be present in the abdominal region. 



Haploscoloplos kerguelensis (Mcintosh). 



Scoloplos kerguelensis, Mcintosh, 1885, p. 355, pi. xliii, figs. 6-8; pi. xxiiA, fig. 19. 



Occurrence. St. 164 (numerous juv.); WS 742 (i). 



Specific characters. The specimens from St. 164 are all young, measuring between 

 5 and 10 mm. in length by about 0-5 mm. in breadth. That from St. WS 742 is much 

 larger, incomplete posteriorly and measures about 30 mm. by 2 mm. at the widest part. 

 The prostomium is definitely pointed. The large specimen from St. WS 742 has 14 

 thoracic chaetigers and the gills begin at the 15th, and in the small specimens there are 

 nine or ten thoracic chaetigers and the gills begin at about the 12th. There is no flat- 

 tening of the dorsum in the thoracic region. The feet are provided with small, triangular, 

 postchaetal languets and the bristles both dorsally and ventrally are crenate capillaries. 



In the hinder region the gill is the usual flattened more or less leaf-shaped structure. 

 The dorsal cirrus increases in size from before backwards and in the young specimens 

 becomes filiform ; in the larger specimen, however, it remains narrowly lanceolate and 

 foliaceous rather than filiform. Moreover, the ventral ligule in this specimen has a 

 bifid tip, whereas in the younger specimens it remains single. The bristles are crenate 

 capillaries, the ventral being more slender than the dorsal. In the young specimens the 

 dorsal rami also carry a few forked bristles. 



Remarks. I have examined Mcintosh's types and the complete absence of thoracic 

 hooks is irreconcilable with Eisig's view that Mcintosh's species is synonymous with 

 armiger. Fauvel (igi6, p. 443) has given an account of some young specimens of 

 kerguelensis from the Falkland Islands which agrees fairly well with the present young 

 examples from the South Orkneys. The forked bristles in the dorsal rami of the hinder 

 region which he records are present in my young specimens, but absent from the larger 

 example. They are probably characteristic of a certain stage of growth. I have not seen 

 any acicular bristles similar to those described by Fauvel for the ventral rami. 



Benham holds that the worms referred by Gravier (191 1, p. 108) to kergueletisis are 

 distinct and conspecific with a number of specimens from off Adelie Land which he has 

 named S. mawsoni. Benham's mawsotii has 1 1 anterior segments, no forked bristles or 

 acicula and the gill beginning on the 12th chaetiger. I confess that I am not convinced 

 that Benham's species is more than a stage in the growth of kerguelensis. The fact that 

 some of the specimens were sexually mature does not necessarily mean that they were 

 fully grown. My young specimens from the South Orkneys are very close to Benham's 

 account of mawsoni, but they have forked bristles which Benham regards as a differential 

 character. 



I have described two species of Haploscoloplos, panamensis from the Panama region 

 and torttigaensis from Dry Tortugas. H. panamensis differs from kergueletisis in having 

 subpodial papillae in the hinder part of the thoracic region and in having bilobed ventral 

 rami in the hinder region. H. tortngaensis has an intermediate cirrus in the hinder region. 



