302 NEREIS DTTMERILIL 



5. Nekeis dum'eeilii, Audonin fy Edwards, 1833. Plate LII, fig. 5 ; Plate LX, figs. 10-10 c 

 —head, etc.; Plate LXX1I, figs. 4-4/— feet; Plate LXXXI, figs. 4-4 c— bristles. 



Specific Characters. — Head of the normal shape with four large ejes. Occasionally 

 the elevated central region has a wedge-shaped patch of white from the posterior pair of 

 eyes to the tip. Tentacles of moderate length. Tentacular cirri long, ranging from one 

 third the length in small examples to one fifth the total length in larger ; the longest is 

 the dorsal of the second pair. Body 2\ ins. long, and of seventy to eighty segments. 

 Colour, various shades of yellowish-brown, enlivened by the red dorsal vessel. Anterior 

 fifth of the dorsum minutely dotted with brown, and more brightly iridescent than the rest 

 of the dorsum. Minute white grains occur over the central vessel. Behind the anterior 

 fifth white grains are distributed over the whole dorsum. Occasionally small specimens 

 are greenish-yellow, and have rather large yellow grains. Ventral surface greenish 

 anteriorly, the rest of the same hue as the dorsum. Proboscis has two slightly translucent 

 amber-like maxillge with six teeth. Paragnathi comparatively feebly developed. Dorsally 

 the maxillary segment in extrusion has in the ordinary examples no paragnathi, but a 

 short double row of small paragnathi (II) occurs on each side. Ventrally a patch of 

 oblique but parallel pectinate rows of minute denticles, the whole having a somewhat 

 triangular outline and a rasp-like surface, occurs near the base of each maxilla (IV), 

 and between are two rows of minute denticles (III). The proximal segment has dorsally 

 two patches of paragnathi (VI) in front of the palpi, each composed of about two rows 

 of minute points. Ventrally each lozenge-like area has two rows (VII and VIII) of 

 minute paragnathi. 



The first foot has a proportionally large and long dorsal cirrus and three rather 

 long lobes, besides the setigerous process. A tendency to the increase of the dorsal 

 region is apparent at the thirty-seventh foot and becomes conspicuous at the fifty-seventh, 

 with the presence of two opaque glandular masses in each foot. The ventral cirrus is 

 somewhat short throughout. Bristles homo- and heterogomph, the former with tapering, 

 boldly spinous terminal pieces, the latter with short tips, and a very short spinous edge. 



Epitokous Form. — The head in the epitokous male is short and rounded, the large, 

 sometimes connate, eyes occupying the lateral regions. Body soft and delicate. Dorsal 

 cirri of the first seven segments dilated and peculiarly modified. The ventral cirri of the 

 corresponding feet are also dilated. At the compressed sixteenth foot the lamellse appear, 

 and the pelagic condition is fully developed at the thirty-seventh foot, the great lobes 

 being very thin, and finely and somewhat regularly veined. The dorsal cirrus has a 

 series of prominent papillas on its lower edge. The long swimming bristles give a glassy 

 sheen to the sides. 



Synonyms. 



1833. Nereis Dumerilii, Aud. & Edw. Ann. Sc, Nat,, t. xxix, p. 218, pi. xiii, f. 9—12. 



1834. „ „ idem. Annel., p. 196, pi. iv a, f. 10—12, 

 1840. ., ., Johnston. Ann. Nat. Hist., v, p. 174. 



a a » G-rube. Actin. Echin. u. Wiirm., p. 73. 



1843 « » » H- Ratlike. Beitrage Fauna Norweg., p. 163, Taf. vii, f. 4, 5. 



