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 centi- 

 pede 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 conchilega) 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 Nema- 

 todes, and in the shore-pools there are Plana- 

 rians or " living films " which glide along mys- 

 teriously by means of invisible lashes or cilia. 



