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Records of the Australian Museum (2009) Vol. 61 
Figure 33. A-N, Serpula watsoni Willey, 1905. A-I, from AM W21408; J-N, juvenile 
specimen from AM W21446. (A-G) bayonet-shaped special collar chaetae; (H) 
thoracic uncini, (/) anterior abdominal uncini; (7) tube; (K) operculum and radioles 
separated body of worm (AO; (L,M) two views of operculum; dorsal view of worm. 
mm; length of operculum and peduncle 1.5 mm, length of 
operculum 0.5 mm, and length of abdomen 1.6 mm. 
Tube. White, trapezoidal in cross-section in first specimen, 
with two uniformly developed smooth longitudinal 
ridges along its crest, with a narrow, comparatively deep 
longitudinal groove running between them (Figs 32A,B, 
33J). Along the lateral base of each longitudinal ridge is a 
lateral longitudinal groove that tucks underneath the ridge 
and demarcates it from the rounded fla nk of that side. Lateral 
edge along each flank decreases in thickness laterally. A 
translucent granular overlay is present (Fig. 32B). Tube 
similar in second specimen, with regard to longitudinal ridges 
and grooves, but the median longitudinal groove is not deep 
where parts of the tube appear to have grown unattached to 
the substratum (Fig. 32H,J); the typical form, however, is 
recognizable in the more horizontal part (Fig. 321). 
Juvenile tube white, shiny on inside; two smooth 
longitudinal ridges present along its crest, with a longitudinal 
groove between them; latter wide compared to size of tube 
(Fig. 33 J); a faint granular overlay discernible along its lateral 
borders; internal tube structures absent. 
Worm. Operculum bell-shaped (Fig. 32C-F,K-M); its 
proximal part swollen and bulbous before it joins the 
peduncle; constriction between operculum and peduncle 
sharp (Fig. 32D,F,K,M). Numbers of marginal opercular 
lobes in the three specimens examined: 29, 23 and 25; 
triangular with blunt tips in juvenile specimen (Fig. 32C-F); 
rounded to squarish in the others (Fig. 32K-M); cuticle 
thin and translucent in younger specimens (Fig. 32C-F); 
somewhat thicker in older specimens (Fig. 32K-N). As seen 
in figures mentioned, tubercles present along the radii, more 
prominent in older specimens. Funnel-shaped opening of the 
