Pillai: Serpulid polychaetes from the Australian Kimberleys 
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Figure 35. A-J, Spiraserpula snellii Pillai & ten Hove, 1994, AM W21475 (continued), (A,B) whole worm in two parts 
[A, shows ventral groove along the abdomen, which is applied along the ventral longitudinal internal tube structure]; 
( C,D ) two further views of anterior part of worm; ( E-G ) bayonet-shaped special collar chaetae; ( H) thoracic uncini; 
(7) anterior abdominal uncini; ( J) posterior abdominal uncini. 
one side drawn into a long tapering process; possess long 
shafts that protrude conspicuously from the abdominal wall; 
although may not be evident in adults of certain taxa, they 
are present in juveniles. 
Remarks. Hartmann-Schroder (1996: 565) uses the 
Subfamily uses Uchida’s Spirobranchinae, including the 
genera Pomatoceros and Placostegus under it. However, 
the subfamily consists of the single genus Spirobranchus 
(Blainville, 1818) in the present paper, with the genera 
Pomatoceros Philippi, 1844, and Pomatoleios Pixell, 1913, 
synonymized with it. Uchida (1978) included, among others, 
the genera Spirobranchus, Pomatoceros, Pomatoleios and 
Ditrupa, under it. However, Regenhardt (1961) erected the 
new subfamily Ditrupinae with type genus Ditrupa Berkeley, 
1835, and Ditrupa arietina (Muller, 1766) as type species. 
The above emended diagnosis of Spirobranchus takes 
into account the side on which the operculum occurs. It has 
been reported as being always a modification of the second 
radiole of the left side in almost all its species. It would, 
however, be useful to note that, out of a hundred of the 
Mediterranean Pomatostegus polytrema (Philippi, 1844) (= 
Spirobranchus polytrema in the present paper) examined by 
Zibrowius (1964), only one had the operculum arising on 
the right. According to Imajima and ten Hove (1984) it may 
arise from the left or right in S. decoratus Imajima, 1982. 
Although this difficult genus has received much attention 
in recent decades, the taxonomy of its species is yet to be 
