Pillai: Serpulid polychaetes from the Australian Kimberleys 
129 
Figure 22. A-E, Hydroides spiratubus n.sp., from holotype AM W21392. (A) 
spiral tube; stippled areas represent the light caramel-coloured material laid 
along its concave sides; ( B ) worm removed from tube, showing the operculum, 
pinnule-free radiolar tips, and abdomen; (Q another view of worm showing 
arrangement of anterior abdominal tori; ( D ) lateral view of operculum; (E,F) 
vies of operculum; F, bayonet-shaped special collar chaeta of Serpula narcon- 
ensis Baird, 1864, from holotype BMNH 1972.75, Narcon Island, Erebus and 
Terror Admiralty Southern Seas Expedition 1839-1843, for comparison with 
other Serpulinae, sensu stricter, note: it is unusual for members of the subfamily 
to have distally serrated special collar chaetae, i.e., serrated at the end of an 
extremely long unserrated notch. 
abdominal neurochaetae almost capillaries, except 
that their tips are serrated along one side (Fig. 23 J) 
as in many Serpulinae s.str. 
Remarks. Like Hydroides spiratubus n.sp., three 
other species of Hydroides are known to possess 
a modified coronal spine that is T-shaped in cross- 
sectional appearance, together with unmodified 
coronal spines ending in swollen to T-shaped tips. 
They are, H. albiceps (Grube, 1870), H exaltatus 
var. vesiculosus Fauvel, 1923, from lies Gambier, 
French Polynesia, and H. trivesiculosus Straughan, 
1967, from Queensland. 
Ten Hove kindly sent his extensive original 
notes and drawings on several collections of 
the above species, including those of his re¬ 
examination of specimens and type specimens 
described by various authors from Elat in Israel 
to locations in the Indo-West Pacific. They will 
be briefly referred to in the following discussion. 
Willey (1905) and Pillai (1960) describe H 
albiceps from Sri Lanka. However, the latter 
appears to be different from those those studied by 
ten Hove. Willey describes the coronal processes 
of a small specimen, only 7.0 mm long, from Galle 
(1905: 312, pi. VII, figs 180, 180a) as follows. 
It consists of “eight nearly erect slightly curved 
virgulae and a laterally compressed ovate lamina 
dorsalis, the latter being a direct continuation 
of the columella and bearing a pair of broad 
dorsolateral chitinous hamuli.” Willey uses the 
diminutive plural “hamuli” of the Latin word 
“hamus”, meaning hook, to describe the small 
lateral spine on each shoulder of the modified 
coronal process. He describes the corona of a 
larger specimen, 20.0 mm long as consisting of 7 
processes, and that the modified coronal process 
(lamina dorsalis) as being “quite flattened except 
at the back.” According to Willey’s figure (1905: 
pi. VII, figs 180, 180a) the unmodified coronal 
processes are outwardly curved and pointed at 
their tips, and its infundibular processes do not end 
in swollen to T-shaped tips. Its modified coronal process is 
laterally flattened, except dorsally where it bears a pointed 
laterally directed “chitinous” spine on each shoulder. Pillai’s 
description and figures (1960: fig. 4L-M), based on a 
collection of 33 specimens from the Pearl Banks, agrees with 
that of Willey (1905) with regard modified and unmodified 
coronal processes and the infundibular processes. Tubes 
are “quadrilateral in cross-section”, the attached side being 
wider than the flattened opposite side, and the two upper 
angles of the latter being sometimes drawn out into low 
lateral longitudinall ridges. No spirally coiled tubes were 
observed. Bayonet-shaped special collar chaetae possess two 
conical processes at the base of the blade. Throracic uncini 
bear about 7 teeth in a single row. 
Although the collections studied by ten Hove: PHYT 3436 
from El Bilyayim, Gulf of Suez, and the following collections 
from Elat: NS 2149; 61-73; NS2148 RS TAV; NS2142 TAV; 
NS2145 TAV, and Elat8 are superficially similar to those 
described by Willey and Pillai from Sri Lanka, there are 
three differences between them. Firstly, the modified coronal 
process of the former does not possess the pair of pointed 
mediolateral spines that occur in the latter. Secondly, the 
unmodified coronal spines of the former end in swollen to 
T-shaped tips, whereas they are simple, outwardly directed 
and pointed in the latter. Thirdly, the tips of the infundibular 
radii in in the former vary from being pointed to somewhat 
swollen, whereas they are simple and pointed in the latter. 
The numerous specimens of H. albiceps examined and 
figured by ten Hove from collections in the AM, Sydney, 
from Australia (Lizard Island, Townsville, Barney Point, 
Gladstone, Shoal Point, Tannum Sands, Burleigh, Cairns, 
Pats Point, Mackay, Noosa Heads, York Peninsula and Port 
Moresby), and Ambon, also agree with the non-Sri Lankan 
collections discussed above. Ten Hove does not describe 
spirally coiled tubes in any of the collections examined, a 
characteristic of H. spiratubus n.sp. But according to his 
drawings of the tubes from AM W3975 (Barney Point, 
Gladstone) AM W3960 (Shoal Point) and AM W3961 
(Tannum Sands) are trapezoidal in cross-section and bear a 
pair of longitudinal ridges. 
The second species that needs to be compared with H. 
spiratubus n.sp., is H. exaltatus var. vesiculosus Fauvel 
