86 NATURAL HISTORY OF OUR SHORES 



anterior end which are often of brilliant colours, and open, 

 flowerlike, above the top of the tube dwelling (see Fig. 

 35). These are beautiful and conspicuous objects in certain 

 situations in low-tide pools. 



Many lead an active and roving life, swimming even at 

 the surface of the sea, while others never come to light. 

 Many are clothed with beautiful scales, which are arranged 

 in double row, tile-fashion, along the back (Polynce, Nykia, 

 Sigalion), and many gleam at night with a bright green 

 phosphorescent light. 



It will be only here and there that we shall take an 

 example, for even a list of their names and a brief descrip- 

 tion would form a fair volume. 



We shall first consider the common " Lug-worm " of 

 the fisherman (Arenicola marina or Arenicola piscatorum 

 Fig. 36). 



This is very common on all sandy shores, as is manifest 

 by the little towers of " Casts," so called, that are seen on 

 all sides. Arenicola is not a predaceous worm, but only 

 fills its stomach with the soil in which it dwells to absorb 

 whatever organic matter it may contain like the earth- 

 worm of our fields and gardens, and the " Casts " are the 

 sand which has been moulded into form and expelled after 

 transit of the worm's intestine. 



The worm itself is buried about nine inches below the 

 surface, and is rarely seen unless it is dug out. There are 

 two openings to its burrow, one marked by the cast and 

 near it a funnel-shaped hole. The anterior end of the 

 worm is towards the latter, its posterior end toward the 

 former. The worm is about six inches long, of a greenish 

 brown colour. 



The anterior third of the body is inflated, and without 

 appendages. The remainder of the body is slender, and 

 the middle portion alone is furnished with branchial tufts 

 and bristle-clad feet. 



