454 NEMATONEREIS UNICORNIS. 



1864. Lumbriconereis unicornis, Claparede. Glanures Zoot., p. 112, pi. iv, f. 2. 



1865. Nematonereis pectinifera, De Quatrefages. Hist. Nat. des AnneL, p. 372. 

 » j, Grubei, idem. Ibid., p. 373. 



contorta, idem. Ibid., Explic. des Planches, p. 13, pi. viii, f. 24—27. 



,, Lumbriconereis unicornis, idem. Ibid., ii, p. 652. 

 1868. „ oculata. Elders. Borstenw., p. 374, Taf. xvi, f. 19—22. 



„ Nematonereis unicornis, Claparede. Annel. Nap., p. 151. 

 1875. ,, ; , Marion and Bobretzky. Ann. Sc. nat., 6 e ser., t. ii, p. 15. 



1879. ,,■ v Langerhans. Zeitsclir. f. wiss. Zool., Bd. xxxiii, p. 295. 



1885. „ „ Cams. Fauna Medit., p. 214. 



1903. ., „ Mcintosh. Ann. Nat. Hist., ser. 7, vol. xi, p. 560. 



1004. „ „ Allen. Journ. M. B. A., n.s., vii, p. 225. 



1905. „ „ Willey. Rep. Ceylon Pearl F., iv, p. 284. 



,, ,, oculata, Graeffe. Arbeit. Zool. Stat. Triest, xv, p. 321. 



1906. , „ De St. Joseph. Ann. Sc. nat., 9 e ser., t. iii, p. 213. 



Habitat, — Amongst muddy sand in fissures of gneiss between tide-marks, St. Peter 

 Port, Guernsey. Plymouth (Allen). 



Ceylon (Willey). Off Pernambuco. Cape Verde Islands. Sea Point, Cape Town, 

 probably. Canaries and Madeira (Langerhans). 



Head evenly rounded in front, forming a short blunt cone. At its posterior border 

 are two large black eyes, and between them a subulate median tentacle which is less than 

 the antero -posterior diameter of the head. 



Body five to six inches or more long, pale pinkish iridescent anteriorly with a red line 

 from the dorsal vessel, and a central streak from the intestine, whilst this posteriorly is 

 pale orange from its glands, the rest being pale cream-coloured. The annelid is nearly 

 cylindrical from end to end. 



Proboscis (Plate LXIII, fig. 5). — The maxillae are short and strongly hooked anteriorly 

 — like the upper half of the letter S. At the posterior end a dark brown band separates 

 them from the posterior appendages which have an elongated conical outline. The 

 anterior plates have a triangular brown patch in front. The great dental plates have a 

 series of comparatively large teeth four or five in number. The mandibles (Plate LXIII, 

 fig. 5 a) are hatchet-like, and the expanded anterior blade is marked by parallel lines. 



The first two segments are devoid of feet, the anterior being somewhat broader than the 

 posterior. The first foot is small and has a short, subulate, almost conical dorsal cirrus, and 

 an ovate, massive ventral cirrus. The setigerous region is little developed, being less than 

 the ventral cirrus, and has a single dark brown spine. The dorsal bristles have tapering 

 winged tips. Below the spine is a group of jointed hooks, the distal process being winged 

 and bifid at the tip — the whole differing little from the same structures in the tenth foot. 



At the tenth foot (Plate LXXV, fig. 3) the dorsal cirrus has considerably elongated 

 — forming a subulate organ. It is now separated by a considerable interval from the 

 deep, truncated setigerous region, bearing dorsally a group of four winged bristles 

 (Plate LXXXIV, fig. 1), which have the tips dilated above the shaft and then rather 

 abruptly narrowed to finely tapered and long processes. The wings are minutely 

 striated. Below there is a group of smaller winged bristles with finely attenuate tips. 

 Appearances would seem to indicate that the setigerous lobe has a flap. 



