172 



Dr. Johnston on the Irish Annelides. 



been preserved for some years. It would have been easy to 

 have multiplied figures exhibiting still other dissimilitudes, but 

 the pattern, though modified, is always essentially the same. 

 Some of these differences proceed from selecting feet of non- 

 corresponding segments ; others are produced by differences 

 in the condition of the worm when killed, — for example, from 

 its being filled with ova or not ; and others again from a dif- 

 ference in the strength of the spirits in which the specimens 

 are placed. In some specimens which had been long preserved, 

 the post-occipital segment was scarcely larger than the one 

 behind ; but when alive the great proportional size of the 

 former is always very obvious. 



Though the specific name is less appropriate than it might 

 be made, I have deemed its restoration better than the impo- 

 sition of a new one ; for the opportunity of consulting Muller's 

 figure, afforded me by my kind friend Mr. Alder of Newcastle, 

 has fully convinced me that this is not the N. pelagica of Lin- 

 naeus, nor N, verrucosa of MuUer. The true synonyms of 

 N, viridis appear to be the following : 



Nereis coerulea, Penn. Brit. Zool. iv. 93. pi. 27. fig. sup. edit. 1812. Turt. 



Gmel. iv. 88. Turt. Brit. Faun. 135. Stew. Elem. i. 390. — Lycoris 



viridis, Johnston in Zool. Journ. iv. 419. — Lycoris margaritacea, Ihid. 



.in lib. cit. 420 ; and in Mag. Nat. Hist. vii. 230. — Nereis pelagica, A7i- 



nals Nat. Hist. iii. 290. 



3. iV.j9eZa^ica, post-occipital segment 

 about twice as long as the second ; ten- 

 tacular cirri longer than its transverse 

 diameter; serratures of the jaw not 

 reaching the apex ; branchial lobes of 

 the feet papillary, subequal, the dorsal 

 one more or less humped ; superior 

 cirrus twice as long as its lobe. 



Fig. 4. 



Fig. 3. 



Nereis pelagica. 



