THE SCHOOL OF THE SHORE 15 



spiders " or Pycnogons, perhaps related to both 

 true spiders and Crustaceans. A few true 

 spiders among the rocks, some insects near 

 high - tide mark, and an occasional centipede 

 must also be included in the shore-fauna. 



WORMS. The higher worms or Ringed 

 Worms (Annelids) are well represented on the 

 shore ; but one must dig to see the best of them. 

 Thus the yard-long many-footed Nereis virens 

 burrows in the sand close to the rocks ; the 

 castings of the fisherman's lobworm (Arenicola) 

 are much in evidence on the flat beach ; the 

 strange sea-mouse {Aphrodite), shaggy with 

 iridescent bristles, is often cast up from greater 

 depths. The sand-binding worm (Lanice con- 

 chilega) makes tubes of sand-particles neatly 

 fastened together ; the lime-tubes of Serpula 

 are common on shells, and of Spirorbis on 

 seaweed. 



Besides the higher worms or Annelids, with 

 a ringed body, there are many others of lower 

 degree. Where there is rotting we may find 

 thousands of small threadworms or Nematodes, 

 and in the shore-pools there are Planarians or 

 "living films "which glide along mysteriously 

 by means of invisible lashes or cilia. 



