Pillai: Serpulid polychaetes from the Australian Kimberleys 
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Figure 15. A-G, Hydroides minax (Grube, 1878), from AM W202951: (A) part of tube on substratum; ( B,C ) two different views of 
worm; A shows arrangement of anterior abdominal tori of the two sides which meet or almost meet dorsally; (D,E) two enlarged views 
of operculum; ( F,G ) two bayonet-shaped special collar chaetae. 
Tube. White, maximum external diameter at its anterior end 
2.7 mm; its surface is irregular, but two somewhat rounded 
and irregular longitudinal ridges with a moderately wide 
shallow longitudinal gap between them can be recognized, 
and an irregular flange on either side (Fig. 17A) which gives 
it a roughly trapezoidal cross-sectional appearance. Irregular 
transverse ridges present, also between the longitudinal 
ridges. Fractured end of tube reveals a moderately thick 
caramel to light brownish translucent inner layer, with patchy 
brownish pigment inside. 
Worm. Coronal and infundibular processes transparent 
light yellow and with brownish tips. Corona heterospinous 
and consists of 9 spines, all devoid of medial, lateral and 
basal processes (Fig. 17D); enlarged dorsal spine somewhat 
swollen in middle and ends distally in a hook curved towards 
