102 NATURAL HISTORY OF OUR SHORES 



each bristled at the ends. Fig. 40 gives a general idea of 

 its appearance, but as the species does not lend itself readily 

 to " posing " the details are not very well seen. 



This worm lives in portions of the shore where the ground 

 is a mixture of sand and oozy mud, near the lowest tide 

 zone. It constructs a tube of parchment-like texture, of 

 ample proportions, generally about two feet long, and this 

 tube is buried in the ground in the shape of the letter U. 

 both ends projecting an inch or two above the surface. 

 Often one end of the tube is bifurcate, or even in three 

 branches, as if the original opening had perhaps become 

 blocked, and auxiliary openings, with bits of new tube, 

 added. 



Although the worm is not often seen, fragments of these 

 large tubes (they are about three quarters of an inch in 

 diameter) are frequently cast on shore. 



This worm has almost invariably a lodger in its tube, 

 one of the beautiful scale-clad worms (Nykia cirrosa). The 

 specimen shown in Fig. 36 was taken in the tube of a 

 Chsetopterus. 



Cha3topterus is phosphorescent, and at night a halo of 

 light surrounds its lowly dwelling. 



As a subdivision of the worms, although not having many 

 affinities with them, are the so-called " Spoon- worms " 

 (Sipunculus, etc.). They belong to a class termed the 

 Gephyreans. These are smooth, cylindrical bodied animals, 

 with apparently no sign of life about them. 



Some forms are abundant on every shore, even at the 

 highest tide level, where there is a mixture of loose stone 

 and gravel. The most familiar species is Phascolosoma 

 Icevis. It is about as thick as a porcupine quill, and about 

 four inches long, tapered towards the anterior end, at the 

 centre of which, surrounded by short ciliated tentacles, 

 is the mouth. The body is perfectly smooth, and usually 

 of a straw colour. 



