892 Dr. Johnston on the British Nereides. 



the bristles oi the superior fewer and more slender than those 

 of the inferior; all of them two-jointed, the terminal piece ob- 

 liquely set, setaceous, smooth, liable to be broken off: spines 

 one to each bundle of bristles, acute, dark-brown : tail termi- 

 nated with two short styles. 



I have seen specimens which were of a uniform grass-green 

 colour, tinted only with fuscous-brown about the head. At 

 some seasons of the year, in autumn especially, the body is 

 often blotched with large irregular yellow patches, and traversed 

 with red lines, occasioned by the viscera appearing through the 

 skin. A red vessel may be always traced down the middle of 

 the back, giving off, to each foot, a small branch, which is 

 again slightly ramified ; and a similar vessel runs along the 

 tlat ventral surface, which is marked with a median furrow. 

 But after being macerated in spirits the colours entirely dis- 

 appear, the worm becoming of a uniform dead yellowish white 

 with a pearly gloss, most distinct on the belly, and a tinge of 

 brown sometimes remains on the back. When allowed to die 

 gradually in sea-water, the animal often pushes forth its well- 

 armed proboscis, which is marked with pale anastomosing 

 lines in a longitudinal direction, probably of a muscular cha- 

 racter. In dying it relaxes considerably. Fresh water is an 

 immediate poison to such individuals as are taken from the 

 sea-shores ; yet a partial mixture is not unfavourable to its 

 habits, for the species is to be found abundantly burrowing, 

 like an earth-worm, in mud in the brackish water of our tide 

 ways and littoreal marshes. 



The figure in the c Magazine of Natural History 5 is too short 

 proportionably, and does not give a good idea of the worm. 

 That either of Basten or of Pennant is sufficient to identify 

 their species with the one before us : and I have taken these 

 figures as my guide to the synonyms quoted, for the descrip- 

 tions do not always tally; but to expect a coincidence between 

 the descriptions of Linnaeus or Muller and those drawn up by 

 naturalists of the present day would be unreasonable. I can- 

 not refer Nereis pelagica to any species described by Audouin 

 and Milne Edwards. Their description and figure of N, Beau- 

 coudrayi show that it is very nearly allied, but it differs in 

 having only 100 segments, though of equal or rather superior 



