NEREIS. 149 



It is the largest of the whole tribe, in as far as I am aware, inhabit- 

 ing the Scotish seas. Likewise its characters are so distinct, that it can- 

 not be readily mistaken. 



Length two feet ; breadth half an inch. Body composed of above 

 400 segments, always multiplying with age. Between the segments are 

 three or four interannulations, on the prolongation of which the exten- 

 sion of the specimen seems to depend. Each segment consists of a 

 transverse central portion, with a broad flattened organ, equally large, 

 on each side, from the lower part of which a pencil on the body issues. 

 The head is provided with eight definite antennular organs, and some 

 of inferior dimensions, terminate the anterior extremity. The posterior 

 extremity is terminated by a fork. Two dark blue or black eyes are 

 situate on the front of the head ; if there be others, they are very indis- 

 tinct. A stout, yellowish proboscis is projected from before. 



The natural colour of this animal is a fine green ; bluish-green on 

 the centre of the back, iridescent, reflecting a bright blue, as is also seen 

 on the belly. The paddles, as they may be justly denominated, always 

 green. Young specimens, likewise, are wholly green, the bluish colour 

 and iridescence belonging only to the older. 



I have not been able to ascertain that any sheath or external cover- 

 ing is constructed by this Nereis ; but a remarkable profusion of clear 

 glutinous matter is secreted from the whole body, so great, that it may 

 be nearly equal in weight to the specimen itself. 



Probably the natural habitation of all the Nereids is among sand, 

 or in the crevices of rocks, where sand is present. 



During the day this species lurks in concealment, especially under 

 any large flat shell, where it reposes and unfolds from its many convolu- 

 tions at night, apparently in quest of prey. Perhaps it feeds on the 

 smaller living animals, for which the size and action of the proboscis 

 seem peculiarly adapted. Sometimes, but very seldom, portions of mus- 

 sel have been absorbed ; and once it seemed to me that a large specimen 

 had devoured a smaller, which occupied the same vessel, as its disappear- 

 ance could not be otherwise accounted for. But all kinds of sustenance 



