Dr. Johnston on the Irish Annelides. 175 



Hab. Apparently not unfrequent on the Irish coast. Strangford Lough, 

 and elsewhere on the coast of Down, Win. Thompson, Esq. ; Belfast Bay, 

 Dr. Drummond. 



Body vermiform, flattish or rarely subcylindrical, as thick 

 as a goose-quill, only slightly tapered backwards, smooth, flat 

 on the ventral surface, which has the median line faintly im- 

 pressed. Head small, armed as usual : eyes very large : jaws 

 small, with brown apices, serrated along the edge to the tip 

 or nearly so : tentacular cirri 3 times as long as the diameter 

 of the post-occipital segment, which is of about the same 

 length as the next, and rather narrower. Segments about 80, 

 narrowish, thickened above the origins of the feet, which are 

 well-developed and most crowded on the posterior half of the 

 body. Feet of the anterior segments with 3 short obtuse 

 branchial lobes, the dorsal one more prominent than the others, 

 and the setigerous tubercle minute : of the middle and poste- 

 rior feet the branches are widely remote, with the branchial 

 lobes of the superior branch nearly equal, divaricate, and a 

 large brush of bristles between them : the inferior lobe rather 

 small and simple : superior cirrus twice as long as its lobe : 

 inferior cirrus rather short : spines dark brown : bristles nu- 

 merous, pale yellow, smooth and slender. 



In spirits the worm is generally of a uniform cream or ochre- 

 yellow colour, with a brown line across the front of every seg- 

 ment, and there are two spots of the same or of a rich yellow 

 colour at the base of the dorsal lobe of every foot. These spots 

 appear to be constantly present, and consequently afford a 

 good character of the species, but they are sometimes less 

 perceptible than is desirable. 



6. N. fucata, first and second segments nearly equal ; ten- 

 Fig. 7. 



Nereis fucata. 

 tacular cirri not longer than the head ; jaws finely serrulated ; 



