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Records of the Australian Museum (2009) Vol. 61 
Kimberleys, so suggesting that it belongs to the latter species. 
The early juvenile of S. richardsmithi described above 
shows a possible plesiomorphous condition in an ancestor 
from which S. gardineri, S. richardsmithi and an un-named 
species described later in this account could perhaps have 
been derived. 
As seen from the drawings and notes kindly provided by 
ten Hove in 1996, the new species also occurs in Indonesia. 
Etymology. Named after Dr Richard Smith who considered 
it to be a distinct species (1985, unpublished PhD thesis), 
and his interesting contributions to our knowledge of 
serpulimorphs. 
1.0mm 
Spirobranchus tetraceros (Schmarda, 1861) 
Figs 44A-C, 45A-I, 46A-K 
Pomatoceros tetraceros Schmarda, 1861: 30, plate 21, fig. 
6, from New South Wales. 
Spirobranchus tetraceros (Schmarda).—ten Hove (1970a, 3, 
for further synonymy, in part); ten Hove (1970a: 3-13, 
figs 1-25), Imajima (1986: 8). 
?Spirobranchus tetraceros. —(Dew, 1959: 45, fig. 17). 
Spirobranchus giganteus. —(Dew, 1959: 45, fig. 17). 
Spirobranchus semperi Morch, 1861.—Straughan, 1967: 
246. 
?Spirobranchus tetraceros complex.—ten Hove (1994: 113). 
Material examined. Kimberleys, Western Australia: 2 specimens, AM 
W21441, Condillac Island, 14°06'S 125°33'E, sand with scatter¬ 
ed bommies, intertidal, 12 m, 16 Jul. 1988, st 54; 1 juvenile 
specimen, AM W21397, east side of Fenelon Island, 
14°07'S 125°43’E, from anterior end of tube of Serpula 
jukesii tube, 6 m, st 64. 1 specimen, AM W21398, east 
side of Fenelon Island, 14°07’S 125°43’E, 18 Jul. 1988, 
st 64; 1 specimen without its tube, AM W21399, east 
side of Fenelon Island, 14°07’S 125°43F, 18 Jul. 1988, st 
64; 2 specimens, AM W202956, Lafontane Island, 14°10'S 
125°47'E, 15 m, 19 Jul. 1988, st 68.2 specimens, AM W21411, 
east Montalivet Island, 15°06'S 125°18'E, intertidal, 6 m, 15 Jul. 
1988, st 50. 2 specimens without opercula (one without tube), 
AM W21403, Rob Roy Reef, 14°26'S 124°52’E, 14 Jul. 
1988, st 49; 4 specimens without tubes, AM W202937, 
Lafontane Island, 14°10'S 125°47E, 15 m, 19 Jul. 1988, 
st68.1 specimen, W202940, Coronation Island, 15°05'S 
124°56'E, low tide, 13 Jul. 1988, st 33; 1 specimen 
without tube and incomplete posteriorly, AM W21425, 
south west comer of Lucas Island, 15°13'S 124°31'E, 30 m, 24 
Jul. 1988, st 101.1 specimen, AM W202953, Condillac Island, 
14°06'S 125°33E, sand with scattered bommies, intertidal, 
16 Jul. 1988, st 54. 2 specimens, AM W202954, east side of 
Fenelon Island, 14°07’S 125°43F, 6 m, 18 Jul. 1988, st 64. 2 
specimens, AM W21440, Lafontane Island, MHO'S 125°47'E, 
15 m, 19 Jul. 1988, st 68; 19 specimens, AM W202962, Rob 
Roy Reef, 14°26’S 124°52’E, 14 Jul. 1988, st 49. 7 specimens, 
(2 without opercula), AM W21449, reef, north west of Buffon 
Island, 14°55'S 124°41'E, 20 m, 23 Jul. 1988, st 85; all coll. 
RA. Hutchings. 
Description 
Measurements. Maximum external tube diameter 
in available specimens 4.0 mm; minimum 1.5 mm 
in a juvenile in AM W21441. Total length of larger 
worm in AM W21441,16.1 mm; abdomen 8.9 mm 
long, 78 segments. 
Tube. Mostly covered over by coral; difficult 
to remove without damage to external ridges. 
Colour in larger specimens usually white, with 
a light caramel coloured inner layer; both 
specimens from AM W202953 white, with 
a bluish-grey band along the median ridge, 
especially in their earlier formed parts; 
obtusely triangular in cross-section in older 
Figure 44. A-C, Spirobranchus tetraceros (Schmarda, 1861), specimen from AM W21438. 
(A) tube with worm in situ ; tube obtusely triangular in cross-section, with a low median lon¬ 
gitudinal ridge; ( B ) left dorsolateral view of anterior end of worm showing dichotomously 
branched opercular processes, fringed peduncular wings, fringed inter-radiolar membranes, 
and the thoracic membranes; (C) operculum viewed from anterior end; showing (apparently) 4 
main branches, but actually 3 dichotomously branched processes arising from a common base. 
