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 
(drenicola) 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 Serpu/a 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. 
