Dr. Johnston on the Irish Annelides. 1 73 



Hob. Shore of co, Cork, Geo. J. Allman, Esq. ; Strangford Lough, Wm. 

 Thompson ; Bangor*, Dr. Drummond. (Orkney and Shetland, and coast of 

 the Isle of Man, Edw. Forbes ; Ayrshire, Mr. P. W. Maclagan.) 



This species sometimes attains a length of 8 inches,, with a 

 thickness equal to that of a swan's quill. It is thicker in pro- 

 portion to its length than N. viridis, and has the organs of the 

 head more developed. The proboscis of both species are al- 

 most exactly alike armed, but the serratures of the jaws in 

 N. pelagica do not reach the points, which are rather obtuse. 

 The number of serratures on the jaw appears to be more than 

 10, but not more than 6 of them form prominent denticles 

 on the edge. The segments vary from 80 to 90, and are 

 marked with a few oblique stride on each side above the feet, 

 which are homologous and well-developed. The dorsal 

 branchial lobe is rather larger than the others and somewhat 

 humped ; and from the front of the hump originates the cirrus, 

 of nearly double its length. The inferior cirrus almost reaches 

 to the tip of its lobe. The bristles are smooth. 



The greater number of specimens preserved in spirits are 

 of a uniform pearly iridescent colour with a slight tinge of 

 brown or pink, but some specimens are of a dusky brown 

 with glossy reflections. 



The figure given of Nereis pelagica in the c Encyclop. 

 Method/ Vers, pi. 55. fig. 21 — 23, undoubtedly represents 

 this species ; hence it follows that it is also the Nereis verru- 

 cosa of Muller (Prod. p. 2\J), and of Otho Fabricius (Faun. 

 Grcenl. p. 292.). That it is the Nereis pelagica of Linnaeus is 

 not so certain, for his specific character — " N. segmentis XL. 

 subtus sulcata" — is at variance with the fact ; but as I can 

 scarcely consent that any of our great master's species should 

 be deleted from the " Systema," I willingly appropriate the 

 name to the one before me ; 1 . because such was the opinion 

 of Muller and Fabricius ; 2. because Linnaeus quotes as a 

 probable representation of his species a figure of a worm in 

 Baxter's Opusc. Subsc. tab. vi. fig. 6, with 70 segments and 

 upwards; and 3. because it is very probable that there is not 

 existing a species of Nereis with so few as 40 segments. 



* It is the small town of this name on the coast of Down that is alluded 

 to throughout the paper. 



