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Records of the Australian Museum (2009) Vol. 61 
Figure 11. A-I, Hydroides adamaformis n.sp., from holotype AM 202931. (A) tube, with worm in situ\ (B) anterior end of worm, showing 
operculum, rudimentary operculum and arrangement of anterior abdominal uncinal tori; (C-E) different views of operculum; (F-H) bayonet¬ 
shaped collar chaetae (G, from within collar fascicle); (7) uncini: upper figure, thoracic uncini; lower figure, anterior abdominal uncini. 
from the South China Sea (Fiege & Sun, 1999: fig. 1 IB) the 
distal ends of their sub-triangular unmodified coronal spines 
are quite stubby, somewhat inwardly distended, and bears an 
external anteriorly directed, transverse ridge-like swelling. 
The latter is the external swelling described by Imajima 
(1976) and as “a small chitinous knob on the external side 
of tip (fig. 11 A)” by Fiege & Sun (1999: 123). Hydroides 
adamaformis lacks such an external terminal chitinous knob 
on its coronal spines (Fig. 11A-D). 
Hydroides trilobulus Chen & Wu, 1978 also has a remote 
resemblance to H. adamaformis. However, its corona consists 
of only three swollen processes, and their shoulders do not 
end in lateral spines, and its infundibular radii end in simple 
processes, whereas those of H. adamaformis end in swollen 
T-shaped to crescentic tips. 
Etymology. The specific name adamaformis is derived from 
the Latin adamas = diamond, and refers to the diamond¬ 
shaped external appearance of the coronal processes, 
although their distal ends are curved inwards. 
