PIONOSYLLIS PROLIFERA. 161 



surrounded by a layer of circular and radiating fibres with nuclei. The radiating muscles 



are less developed than in Syllis, but penetrate the epithelial coat. Externally are 

 longitudinal fibres and the endothelial epithelium (Malaquin). 1 



Genus XLIX. — Pionosyllis, Malmgrem, 1867. 



Tentacles, and tentacular and dorsal cirri, articulated, as in Syllis. Proboscis armed 

 with a single tooth anteriorly and with ten soft papillae. Compound bristles subfalcate, 

 terminal piece long and bidentate. Median and posterior segments with long swimming- 

 bristles besides the falcate (Malmgren). Pionosyllis is distinguished by the presence of 

 the single tooth from Syllides, which has an unarmed proboscis ; from Eusyllis by the 

 elongated nature of the terminal pieces of the bristles, though they are bifid in both ; and 

 from Syllis by the bifid terminal pieces to the bristles throughout. 



1. Pionosyllis peolifera, Krohn, 1852. Plate XL VI, fig. 1; Plate LIX, fig. 10 — 

 head, etc.; Plate LXX, figs. 4-6— feet; Plate LXXVIII, figs. 14-14 c, 15, and 16 

 — bristles. 



Specific Characters. — Head hexangular or sub-rectangular with four distinct reddish 

 eyes obliquely arranged on each side, the anterior pair wider apart and with or without 

 lenses. Palpi large and long. Median tentacle has 25 — 30 articulations, lateral 16 — 18. 

 Tentacular cirri long and moniliform. Body three-quarters of an inch or more in length, 

 of a dull straw colour, regularly banded with brown in front. On each side of the 

 segment-junctions a lateral brown bar with a speck in front, whilst in the middle line a 

 shorter bar occurs at a greater distance from the segment-junction and nearly in a line 

 with the speck. Tail with two moniliform caudal cirri. Foot with a long and tapering 

 dorsal cirrus of about 27 or 28 articulations. Setigerous lobe bluntly conical with 

 two terminal papillae. Spines with a peculiar and short point. Bristles of moderate 

 size, translucent, with the convexity of the enlargement at the distal end of the shaft, 

 spinous. Terminal piece rather long, with a nearly straight spinous edge and a minutely 

 bidentate apex. Ventral cirrus fusiform, lanceolate, and does not reach the tip of the 

 setigerous lobe. 



Synonyms. 



1852. Syllis prolifera, Krohn. Arch. f. Xaturg., Bd. xviii, p. 66, Taf. hi, f. 1. 

 1860. „ variegata, Grube. Ibid., Bd. xxvi, p. 85, pi. iii, f. 6. 



1863. „ lussinensis, idem. Ibid., Bd. xxix, p. 46, Taf. iv, f. 9. 



1864. „ fiumensis, Ehlers. Borstenw., I, p. 224, Taf. ix, f. 1 — 9. 

 „ „ Armandi, Claparede. GTlanures, p. 70, pi. v, f. 1. 



„ „ hexagonifera, idem. Ibid., p. 73, pi. v, f. 2. 



1869. Pionosyllis Malmgreni, Mcintosh. Trans. K. S. Edin., vol. xxv, p. 414, Tab. xvi, f. 10, var. 



1874. Syllis lussine?isis, Marenzeller. Sitzb. k. Akad Wien, Bd. lxix, sep. abd., p. 30, Taf. iii ; f. 1. 



1875. „ variegata, idem. Ibid., Taf. lxxii, p. 147, pi. ii, fig. 2. 



1 ' Recher. Syllid./ p. 239. 



78 



