GG6 THE MARINE ANNELIDES OF THE ORDER SERPULEA, 



This is the Serpula most abundantly distributed on the Coast 

 of New South Wales and Tasmania. It occurs only between tide- 

 marks, most abundantly about midway between high and low 

 water marks, and it is thus exposed daily to the sun for several 

 hours. The effect of this exposure however, is greatly diminished 

 by the thickness of the tubes, and by the massive mode of growth 

 of the species, forming dense and thick aggregations often an inch 

 or more in depth, encrusting rocks, submerged wood, the shells 

 of mussels and similar objects. The ordinary length of the tube 

 is about an inch, but varies according to the age of the individual. 

 It is ordinarily closely cemented down to the object on which it 

 grows, the under surface being expanded and adapting itself to 

 the inequalities of the surfaces to which it is apposed. The 

 lumen of the tube is cylindrical, but the wall is irregxilarly 

 thickened, the upper surface, which is sharply marked off from 

 the lateral, being marked by a longitudinal groove, narrow in 

 young tubes, broad and shallow in older ones, and produced 

 anteriorly beyond the rest of the tube as a prominent rounded lobe 

 overhanging the orifice. The lateral surfaces do not quite meet 

 the upper at right angles, but slope slightly outwards. 



The branchiae are about 36 in number. They are rather short 

 and stout, tapering towards the apex. They are characterised, 

 as in many other Serpulidre, by considerable variety in their 

 colouration and markings. The most constant markings are a 

 white band running transversely across the membrane which 

 unites the bases of the stems, a series of white transverse lines 

 or blotches placed at regular intervals along the stems, and, 

 alternating with the latter, a series of parallel pairs of short 

 green or brown longitudinal bands : these green or brown 

 markings are, however, frequently replaced by crimson or purple. 



The operculum has a very short peduncle, the distal extremity 

 not extending beyond the ends ef the short branchiae. In shape 

 it may be compared to an inverted cone, flattened to some extent 

 dorso-ventrally, and with a very oblique base directed towards 

 the dorsal side ; the dorsal side is marked by a longitudinal 

 groove, bounded by a low fold of the integument ; on each side 



