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Records of the Australian Museum (2009) Vol. 61 
Figure 49. A-D, from Spirobranchus sp. 3, BMNH 1959.10.19.28, specimen collected by E.W. & P. Knight Jones from Eden, NSW, 
Australia: (A) ventral view of anterior part of worm; (B, C) anterodorsal and lateral views, respectively, of the operculum; (D) special collar 
chaetae; their chaetal shafts merge gradually with their blades, a boss not recognizable between them, the bend in the chaeta indicating 
the approximate position between them. E-G, Spirobranchus kraussii (Baird, 1864), from a small juvenile in a sample collected by David 
George, Reg. No: NHM, ANEA 2009.23, from Abu Dhabi: (E) shows 7 thoracic chaetigers on the right side; (E) shows absence of a collar 
fascicle on the left side, i.e. only 6 chaetigers on the left; (G) a collar chaeta from the right side where it occurs. It lacks a serrated shaft 
and boss, and is indistinguishable from the other thoracic notochaetae; ( H-K ), Spirobranchus triqueter (Linnaeus, 1767) (= Pomatoceros 
triqueter) two juvenile from British waters specimens for comparison, both show abdominal neurochaetae with conspicuously long shafts 
protruding from the abdomen, besides variations in the operculum; (J) chaetae from the collar fascicle: their shafts lack serrations distally 
as well as a boss; (K) abdominal neurochaetae: one side of its flattened trumpet-shaped distal ends in a tapered process as in the other 
species of Spirobranchus. 
shaft plus boss is about 1.27: 1.0. Thoracic and anterior Abdominal chaetae possessing conspicuous long shafts 
abdominal uncini: saw-shaped, former bearing 8-11 teeth, projecting from the body wall present from the beginning 
and latter 8, in addition to the anterior gouged process. of the abdomen. 
