114 BY THE DEEP SEA. 



struck by its numbers when we observe it thickly Studding the 

 fronds of the Toothed Wrack (Fucus serratus), for the dark 

 olive hue of the Wrack throws up the dead-white Spirorbis 

 tubes very strongly indeed. These tubes and the animals that 

 form them are very like Serpulae, but the tube instead of being 

 more or less straight, or merely twisted, is coiled in a flat 

 spiral, like the shell of the fresh- water Trumpet snail (Planor- 

 bis]. Normally these are very flat at the base, and regularly 

 formed, but where (as in specimens before me) they are 

 densely crowded on the Wrack, there is not sufficient room 

 for this regular growth when they get large, and the outer 

 turns of the spiral are twisted aside and greatly distorted. 

 The worm is very like a Serpula, closing its shell with a 

 similar stopper, but the branchial plumes are not nearly so 

 extensive, these rosy appendages being but six in number in 

 Spirorbis. 



It is impossible to do much work upon the shore before 

 coming upon some specimens of another species of tube-maker, 

 though of a less artistic character. The probability is that 

 you will turn over a flat stone that is partly imbedded in the 

 sand, and under it will find a furrow with an active worm 

 wriggling through it. On glancing at the stone the explorer 

 finds that he has ruined a habitation by forcibly tearing off 

 the roof which had been cemented to the stone for greater 

 security, and continued for some distance beyond the stone on 

 either side. The tube, as a fact, is of great length, so that the 

 worm, which is not more than six inches long, may have 

 ample room for exercise without going into the dangerous 

 glare of daylight, to be seen by some ravenous fish. This 

 species is commonly known as the Sand- worm (Arenicola 

 piscatt<runi). In some districts it is the " Lug." It is popu- 

 larly thought to be a favourite bait with fishermen, and it is 

 so described in all the books ; but in the part of Cornwall 

 where this book is being written the fishermen do not set 

 great value upon it, though they highly appreciate the Wilfry 

 or Woolfry (Nereis pel agica). 



