PHYLLODOCE. 179 



front, but not pointed, the apex armed with four short conical 

 antennae, and a smaller antenna is less perceptible on the vertex. 

 Eyes two*, occipital, dark brown. Mouth with a large clavate pro- 

 boscis, greenish, rough under the magnifier, with minute papillae, 

 edentulous. Post-occipital segment with four tentacular cirri on 

 each side, twice the length of the branchiae, the anterior pair one- 

 half shorter than the others, conical, simple. Segments very nume- 

 rous, often defined by a line of deeper green, shorter than their 

 breadth, smooth, convex dorsally. Branchial leaflets (or superior 

 cirri) lanceolate, slightly compressed, retroflexed, longer than the 

 foot, which is furnished with a bundle of very slender retractile 

 acicular bristles, and with a single spine. Tail terminated with two 

 fleshy styles, similar to the leaflets, but rather larger. 



Ph. viridis lives under stones, or in the crevices of slaty rocks, 

 between tide-marks ; but it abounds most near low-water mark ; nor 

 is it uncommon among the corallines and shells that are never left 

 uncovered by the tide. It is an active species in water, moving 

 forwards principally by the oared leaflets that extend from the sides ; 

 but on dry ground its movement is slow, and the leaflets are kept 

 applied to the sides and brought somewhat under the body. When 

 kept in a vessel of sea-water, deprived of food, the green colour 

 becomes less intense, and allows us to trace a darker intestine down 

 the centre of the body. When specimens are put into spirits they 

 give out a copious green liquor, and tinge the spirit deeply. Im- 

 mersed in fresh water, the worm is evidently pained, but is not killed 

 so instantaneously as some other marine worms are, and in dying 

 does not separate and break in pieces. 



I have not hesitated to refer this species to the Ph. clavigera of 

 Audouin and Edwards, although some slight diflerences may be 

 traced in our figures ; for some experience has brought me to believe 

 that, in comparing figures which have been made under the mag- 

 nifier, we are not to look for an exact resemblance between them. I 

 have seen figures drawn by the same individual, and from the same 

 objects at somewhat distant periods, but with every desire to be 

 accurate, between which the discrepancy was greater than could have 

 been at first imagined. So also I have not expressed any doubt of 

 their species being identical with the Nereis viridis of Otho Fabri- 

 cius ; for the only distinction pointed out by Audouin and Edwards 

 between them is the absence of the odd antenna in the latter, and 

 this is only inferred to be the case from the silence of the Greenland 

 naturahst. But it is no imputation on the acknowledged accuracy 

 of Fabricius to believe that this organ may have escaped his notice ; 

 for, even after having been made aware of its existence, I have some- 

 times found that it was no easy matter to bring it into view, and 

 make it perceptible to others. 



(a) Cullercoats, J. Alder. 



(J)) Holy Island, Br. Johnston. 



* Audouin and Edwards say four, disposed in a transverse line, and very small ; 

 but their figure shows two only. 



N 2 



