Dr. Johnston on the Irish Annelides. 



171 



middle of the body forms almost a part of the setigerous tu- 

 bercle (fig. m.), the union being still more complete on the 

 posterior pairs of feet, on which also there is a mere vestige of 

 the ventral cirrus (fig. />.). The colour of the specimens in 

 spirits is a wax-yellow with a tinge of brown, and a dusky 

 line across the margin of the segments. 



This species very closely resembles Nereis pulsatoria, but 

 in the latter the jaws are serrated to the apex, and the termi- 

 nal joint of the bristles is finely serrulated along one edge. 



2. N, viridis, post-occipital segment twice as long as the se- 

 cond ; tentacular cirri once and a half or nearly twice as long 

 as its breadth ; jaws serrated to the point ; feet homologous, 

 with papillous subequal branchial lobes, the dorsal one (of the 

 posterior feet especially) somewhat humped ; superior cirrus 

 scarcely reaching beyond the apex of its lobe ; upper setige- 

 rous tubercle obsolete. 



Fig. 2. 



Nereis viridis. 

 Hah. Strangford Lough, Wm. Thompson, Esq. ; co. Cork, Geo. J. All- 

 man, Esq. 



To the description of this species given (under the name of 

 N, pelagica), in the Annals, vol. iii. p. 291, I have only to add 

 that the jaws appear to have 10 serratures on their cutting 

 edge. To show how far the feet of the same species may vary, 

 I have given the above figures, — the three upper ones taken 

 from an individual immediately after being killed by immer- 

 sion in spirits, — the three lower ones from a specimen that had 



N 2 



