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Records of the Australian Museum (2009) Vol. 61 
Figure 12. A-F, Hydroides exaltatus (Marenzeller, 1885). A-C from a specimen separated from AM W202941: (A, B) two tube fragments; 
(C) anterior part of worm showing operculum, radioles and arrangement of anterior abdominal tori. D-F: from a specimen in AM W202964; 
( D ) tube fragment; (E,F) two views of operculum; (E) also shows rudimentary operculum. 
spines meet and appear like demarcating lines between the 
bases of the main spines. It is evident, therefore, that the short 
medial spine on the coronal spines is a variable character in 
H. exaltatus. It may not be developed in some, or even in 
all the coronal spines; they may also vary in position, being 
closer to the base in some individuals than in others. 
Another variation observed concerns bayonet collar 
chaetae. Although Imajima (1976) states that collar chaetae 
may bear one or two conical teeth at the base of the blade, 
they bear more than 2 in the Kimberleys material (up to 6 
were counted), composed of 1 or 2 main teeth and the rest 
of smaller accessory teeth (Fig. 13D-I). 
