284 NEREIS CITLTRIFERA. 



but considerably narrower than the corresponding segment in N. pelagica. The body 

 is greenish anteriorly, pale brownish in the middle and again greenish posteriorly. A 

 deep purplish blue line extends along the dorsum, with the sinuous dark red or purplish 

 blood-vessel branching in each segment and with long twigs directed backward. An 

 orange or golden iridescent hue exists on each side of the vessel, whilst the bases of the 

 feet and these organs themselves are generally greenish. The posterior part of each 

 segment has a greenish-black bar extending quite across the junction, and in addition 

 another on each side anteriorly — formed, as it were, of a single bar separated by the 

 dorsal blood-vessel. These markings become indistinct when the brownish median hue 

 takes the place of the anterior greenish. Moreover, in the latter region an oblique 

 (longitudinal) whitish streak occurs on each side in every segment, and whitish grains 

 on the segments behind the anterior fourth. A distinct white patch is on the tail at 

 the base of the cirri. The ventral surface is pale and iridescent. The inferior edge of 

 the foot is the most vascular, whilst a series of bright red transverse vessels passes from 

 the posterior border of each towards the interspace. The ventral vessels are of a much 

 brighter red than the dorsal. 



After preservation it is somewhat duskier than Nereis pelagica, and the head and 

 anterior segments have small whitish specks. A pale central patch also occurs at the 

 anterior border of several of these. 



Proboscis. — Dorsally (Plate LX, fig. 7) the strongly curved jaws present about five 

 teeth, and they vary in position, in some the left and in others the right passing 

 above the other. In extrusion the basal or proximal division of the organ has an eleva- 

 tion on each side with a transversely elongated tooth of a bluntly conical shape, whilst 

 between and slightly behind are a median and two lateral teeth, the former being slightly 

 in front. In the maxillary (distal) division of the proboscis a single median tooth 

 occupies the central region dorsally, whilst two crescents occur laterally, one on each side. 

 These are more feebly developed than in N. iielagica. Ventrally (Plate LX, fig. 7 a) two 

 lappet-shaped patches or crescents of similar small teeth occur in a corresponding 

 position, the convexity being inward. In the middle line between the foregoing is a 

 group of about six small teeth. In the basal division of the organ ventrally is a belt 

 formed of a double row of well-marked isolated teeth, the size of these in the rows being 

 nearly equal, though if irregularity occurs in this respect, the smaller teeth are found in 

 the posterior row in extrusion. There is thus a great difference between the single row 

 of large teeth and the "dusting" of smaller prickles as in Nereis pelagica, Some of the 

 large examples have numerous calcareous deposits on the proboscis. 



Specimens frequenting tunnels in peat had stalks of Algge in the hind-gut, and in 

 others from the Channel Islands the fascal masses were enveloped in mucus, and consisted 

 of delicately branched pale Algas with muddy debris. The central parts of the filaments 

 of the Alga3 had been acted on by the gut, leaving only the cellulose exterior. 



The perivisceral or coelomic corpuscles are translucent bodies, spindle-shaped or 

 elliptical in outline, and varying in size (December). Free nuclei lay near or on them. 

 The larger elliptical corpuscles show minute granules, and free granules (minute nuclei ?) 

 floated in the fluid. About a week later during very cold weather a female which had 

 been isolated showed its perivisceral fluid so loaded with small rounded corpuscles as to 



