Pillai: Serpulid polychaetes from the Australian Kimberleys 
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Figure 42. A-H, Spirobranchus richardsmithi n.sp. from specimens in AM W21442. A,B,E-G, from same specimen. (A, B) dorsal and 
ventral views, respectively, of the whole worm. Note the abdominal chaetae with long shafts; (C) from second specimen: opercular horns 
and disc viewed from the anterior end. D-H, from third specimen: ( D ) ventral view of thorax; (E) right lateral view of operculum and 
thorax; ( F,G ) dorsal and right ventrolateral views of operculum; (H) lateral view of thorax, collar and anterior part of abdomen, showing 
fringed membrane between dorsolateral lobe of collar and base of the radioles, and long-shafted chaetae in anterior part of abdomen. 
Description 
Measurements. All tubes found growing on and covered 
over by coral. Holotype, AM W21433: tube diameter, 6.5 
mm; total length of complete worm in latter 42.4 mm, its 
thoracic width, 3.5 mm; length of operculum and peduncle 
10.7 mm, and the opercular horns 3.5 mm; abdomen 33.7 
mm long, and the number of abdominal segments about 
145. Largest tube diameter, 7.0 mm, occurs in one of the 
paratypes in AM W21433. Total lengths of specimens from 
AM W21442 range from 9.5 mm to 40.9 mm, the latter 
almost the same size as the largest from AM W21433. 
Smallest specimen, from AM W21442, has a total length of 
9.5 mm. However, the early juvenile in AM W21474 has a 
maximum external tube diameter of 0.5 mm; total length of 
worm 4.4 mm, its thorax 0.4 mm wide, length of operculum 
