Pillai: Serpulid polychaetes from the Australian Kimberleys 
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Figure 39. A-J, Spirobranchus corniculatus (Grube, 1862). A-H, from AM W202959: (A) anterodorsal view of operculum of a specimen; 
B-H, operculum of another specimen; ( B-D ) dorsal, left anterolateral and left lateral views of operculum [C, shows a small conical 
process is present on the common basal column of the opercular horns, a variable character]; (£) bayonet-shaped special collar chaeta; 
the serrations along the distal part of the blade are conspicuously long ( F ) thoracic uncini; (G) anterior abdominal uncini; (H) posterior 
abdominal uncini. I,J, operculum of a specimen from AM W202958: (I) right anterolateral view; (7) dorsal view; a conical process is not 
present on the common stem from which the opercular horns arise, unlike in the specimen figured in C. 
Description 
Measurements. Only one out of the 5 specimens in AM 
W202960 has an undamaged tube; its maximum external 
diameter, 4.7 mm. Specimens in AM W202959 are larger; 
maximum external tube diameter of 11.5 mm and tube 
thickness of 2.0 mm; however, the worm is incomplete. 
The largest worm has a total length of 43.8 mm, and about 
217 abdominal segments. The largest thoracic width of 7.7 
was encountered in the incomplete specimen from AM 
W202958. The largest operculum, together with its peduncle 
and horns is 13.5 mm long, horns alone 3.2 mm. Long and 
short diameters of the opercular plate in an older specimen, 
AM W202959, 7.5 mm and 6.5 mm, respectively. 
Tube. Tube colour ranges from yellowish orange in 
specimens from AM W202960, to bright orange, both 
externally and internally, and in the very large incomplete 
specimen from AM W202958. Tube of small complete 
specimen from AM W202960 has a single, somewhat 
smooth, median longitudinal ridge, with fine transverse 
ridges on either side of it (Fig. 38A). 
Worm. Colour: opercular plate rose coloured in four out of 
five specimens in AM W202960 white in fifth; white, and 
its rim and horns bright pink in one specimen; bright pink, 
especially its rim, and tips of opercular horns, in another, 
from AM W202952. 
Operculum occurs on left side in all specimens, 
