SERPUL^l. NEREIS. 243 



part of its body, from which soon afterwards it 

 spreads out its two fan-shaped branchiae or respi- 

 ratory organs, the purple or scarlet hues, the 

 form, and the motions of which are extremely in- 

 teresting. The habitations of the other species of 

 tube-worms referred to, are frequently found in 

 vast quantities lying upon the dry beach, or half 

 buried in the wet sand, and these consist of thin 

 semi-transparent tubes, formed, as already stated, 

 of particles of sand, but not attached, as those just 

 described, to the surface of stones or other hard 

 substances. 



The Nereis is another marine worm of which 

 there are several varieties, some of which may 

 attract the attention of the visitor of the sea-shore. 

 Some of these worms are extremely small, but, 

 like some other very minute creatures, they pos- 

 sess the faculty of emitting light, and are able to 

 illuminate the midnight waters with marvellous 

 splendour. It is in a great measure to these di- 

 minutive annelids that the brilliancy is owing 

 which is perceptible on the agitation of the 

 water. 



Another species is of much greater length, but 

 not possessed of the power of producing light. It 

 is about four inches in length, and of a bluish- 

 green colour, semi-pellucid, and formed of about 

 184 distinct segments. It is frequently found in 

 the sand at low water. Another species is a foot 

 in length, and as thick as a goose quill ; the tail 

 is orange colour, and the rest of the bod} 7 " exhibits 

 a beautiful iridescence. There are several other 



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