54 Dr. Johnston's Contributions to the British Famia. 



Desc. Eo(h/ 1 4 inches long, somewhat compressed, convex on the 

 back, flattened below, of nearly equal thickness throughout, until within 

 an inch or so of the tail, which tapers to an obtuse point ; smooth, green- 

 ish, reflecting a metallic lustre, and changeable, with the margins of the 

 segments purple, and a purple ill-defined spot in the centre of each. 

 Towards the tail the green colour becomes generally diff"used and deeper. 

 Ventral surface perlaceous, tinged with green. Pi'oboscis thick, short, 

 white, cylindrical, without teeth or hard points. Head small, a subtriangu- 

 lar corneous plate, bearing two eyes, and two short conical AntenncB in front. 

 On each side of the head, but arising from the body, are four rather 

 short setaceous Tentacula, the two first shorter than the posterior pairs, of 

 an olive green colour, and thickish. The segments are very numerous, 

 and each bears on each side a leaf-like process, boot-shaped ^>^ 

 placed obliquely, of a brownish colour, slightly clouded, with even 

 smooth margins. Each ybo^ consists of two sub-equal papillary processes, 

 one of which is armed with a fascicle of short black bristles. Tail vdthout 

 filaments ? 



Obs. This fine species I found amongst the refuse of a fishing boat, and 

 it is of course possible that the filaments at the tail may have been torn 

 off". It does not seem to have been described by any author which I have 

 had an opportunity of consulting, but I suspect it may have been con- 

 founded with the Mereis lamelligera, a species which is said to attain even 

 a superior size, and which is readily distinguished by its heart-shaped 

 acutely pointed branchial processes. 



2. Phyll. pulchra. 



Phyll. corpore maculis fuscis seriatim notato ; lamellis branchialibus 

 subreniformibus. 



Nereis maadata ? Fabric, Faun. Groenl. 298. 



Hah. Mare Britannicum. 



Desc. Body slender, 4 inches long, depressed, tapered a little 

 towards each extremity, capable of extension, yellowish, with 

 a longitudinal dorsal row of dark brown spots, and the sides spotted 

 with the same colour. Ventral surface whitish, with a median row of 



