272 NEREIS PELAGICA. 



Dinard, to the south of Halifax, Nova Scotia ; Japan (Marenzeller) ; the eastern shores 

 of Siberia near Anion (Grube) ; Behring's Sea (Marenzeller) ; and var. lunulata, Ehlers, 

 to the Strait of Magellan. Large examples were procured by the 'Valorous' in 

 20 fathoms in the Arctic seas. Specimens were also found on floating seaweed off (rough's 

 Island, South Atlantic, long. 9° 49', lat. 40° |' (Prof. Dickie, Aberdeen), and a variety 

 from Kerguelen. 



This cosmopolitan species thus extends from the British shores to those of northern 

 and southern Europe, the Mediterranean, the Atlantic shores of America, the Pacific, the 

 Arctic, and the Antarctic seas. 



Head (Plate LII, fig. 1, and Plate LX, figs. 6 and 6 a) somewhat rectangular 

 posteriorly and bluntly triangular in front. Four black eyes of considerable size are 

 situated on the rectangular region. The pairs are wide apart and obliquely placed, — 

 that is, the anterior pair is wider apart than the posterior. A pair of short tentacles 

 occurs on the truncated anterior end of the head. From the lateral regions of the snout 

 the palpi project forward and outward as large tumid processes in contraction, and having 

 a terminal articulation which is retractile within the basal region. From the anterior part 

 of the peristomial segment on each side spring two pairs of tentacular cirri, which form 

 a kind of cluster, though the anterior pair arises somewhat lower than the posterior. 

 Each has a long dorsal cirrus and a shorter ventral cirrus, with a basal cirrophore, the 

 longest being the dorsal of the second pair. The peristomial segment is about double the 

 breadth of the average segment, and probably the tentacular cirri indicate that the 

 segment is double, the appendages having been shifted forward. 



Body 4 — 8 ins. long, slightly diminished anteriorly, then remaining of a uniform 

 diameter for some distance, and again narrowing to the tail, where it terminates in a 

 prominent vent, beneath which are two long cirri. The segments are convex dorsally, 

 flattened ventrally, and of nearly uniform breadth and appearance. In colour it is of an 

 iridescent greenish-brown, reddish-brown, or yellowish-brown, the dorsal vessel forming 

 a thin, dull red line, except at the moment of transmission of the blood. Opposite each 

 foot in some are yellowish- white grains. 



There is considerable variety in the coloration, though most show a brownish or 

 fawn-colour dorsally with a greenish or olivaceous shade at the sides and feet. In some 

 a dark grey stripe occurs along each side dorsally at the bases of the feet. Many of the 

 larger specimens have calcareous deposits in circular patches in the skin of the dorsum. 

 The under surface is of a paler, iridescent, or roseate hue, and the anus is often marked 

 by a whitish opacity. 



Proboscis. — In extrusion the organ presents dorsally (Plate LX, fig. 6) two regions 

 — a distal or maxillary and a proximal or basal— mapped out into distinct and somewhat 

 lozenge-shaped areas by linear depressions. From the distal project the two curved 

 horny maxilla) or jaws, with five teeth. On the dorsal margin behind them (Area II) is 

 a crescent of dark brown horny teeth, formed of a posterior curved row, another which lies 

 within (in front of) the former, and a third short row composed of four small prickles at 

 the inner border in front. In the central line (Area I) between these are two teeth, one 

 in front of the other, on an elevation. In front of the palpi is a prominence on each side 

 (VI) with four long prickles or teeth, and slightly behind each a line of prickles (VII and 



