34 THE SEAS 



is the flat Ligia, sometimes an inch and a half long and 

 closely resembling the common woodlouse ; this is every- 

 where abundant and runs about, especially at dusk, usually 

 just above high- water mark, for it is a beast which is by no 

 means dependent on sea water, a slight moisture being 

 apparently all that it needs. Associated with it are a 

 number of sand-hoppers (Talifrus, Orchestia, Gammarus) 

 which, when a stons or pile of dried weed is moved, go 

 jumping away in all directions. Unlike Ligia, they are 

 flattened not from above below but from side to side, a 

 characteristic which separates the group of crustaceans to 

 which they belong, the Tsopods, from the Amphipods. 

 The insects include some beetles, but especially the little 

 spring-tails. Lower on the shore, where the tide always 

 reaches, are found a great variety of worms, such as Nemer- 

 tines, of which the most conspicuous is the long " boot-lace 

 worm " (Lineus) usually tied in a tangled mass which 

 is almost impossible to disentangle without breaking 

 for it may be many yards long. There are also tiny flat- 

 worms which move like semi-transparent films over the 

 surface of stones or on the under side of the surface film in 

 pools. Here we find great numbers of the more highly 

 organized bristle-worms, examples of which are the bright 

 green Eulalia viridis, which is common all over recks, and 

 the yellow Cirratulus cirratus which lives in patches of sand 

 or mud beneath the rocks with only its filamentous tentacles 

 to be seen. Still more worms are found nearer to low- 

 water mark, the commonest being perhaps the handsome 

 Nereis diversicolor, of varied colours and six inches or more 

 in length. It is frequently used as bait, being known as 

 " rag-worm " in many parts. A variety of little worms, 

 broad and flattened with two rows of large scales on their 

 backs, known as Polynoids, are common everywhere. 

 Of the numerous crustaceans the largest and commonest 



