LEIOCHONE BOREALIS. 317 



2. Leioohone borbalis, Arwidsson, 1906. Plate 0, figs. 15, lb a, 16 and 17— head and 

 tail; Plate CVIII, figs. 5 and 5 d and var., fig. 6— bristles and hooks. 



Specific characters. — Cephalic plate with a well-developed rim, the lateral slip being 

 behind the middle. Nuchal grooves short. Eyes at the side of the median peak. Extruded 

 proboscis with a bare belt between the basal and distal papillse. The seventh bristled 

 segment long with the feet anterior. The eighth shorter with the feet behind the 

 middle. Nineteen bristle-bearing segments, and five naked segments posteriorly. Long, 

 sometimes very long, thread-like anal cirri, the ventral the longest, and as a rule paired; 

 longest over the anal opening ; seven to nine or eleven cirri. Bristled segments six to nine 

 with nephridia, their apertures about half the length of the hook-rows behind the feet. 

 Two-thirds of the anterior of each bristled segment from the fourth to the seventh are 

 glandular. At the eighth ventrally the anterior glandular area has lost its free glands 

 anteriorly. The first bristled segment has both kinds of bristles. The hooks of segments 

 1 to 3 are mostly simple with two to six teeth above the main fang, and hairs on the throat 

 appear in the third segment. When fully developed the hooks have seven teeth. The 

 bristles posteriorly show narrow wings. Body 60 to 70 mm. in length. Colour reddish- 

 brown anteriorly. The seventh segment has a blood-red band behind the feet 

 (Arwidsson). 



Tube free, fragile, cylindrical, composed of secretion externally with sand-grains, 

 minute fragments of shells, and minute Foraminifera. 



Synonyms. 

 1869. Pr axilla sp., Mcintosh. Trans. Roy. Soc. Edinb., vol. xxv, p. 421. 

 1872. ? Clymene paucicirrata, Sars. Forh. Yid.-Selsk. Christ. (1871), p. 252. Undescribed. 

 1906. Leiochone borealis, Arwidsson. Skandin. u. arktisch. Maldan., p. 156, Taf. iii, figs. 108 — 115, 



Taf. iv, figs. 116—117, Taf. ix, figs. 281—283, Taf. xi,figs. 

 352—353. 

 1908. ,, „ Bidenkap. Zool. Anzeiger, Bd. xxxiii, p. 267. 



1913. }i )} Nolte. Wiss. Meeresuntersuch., n.f., Bd. xv, p. 33, Taf. i, fig. 11, 



Taf. ii, fig. 31, text-figs. 8—10. 



Habitat.— Dredged in 80 fathoms at the Outer Haaf, Skerries, June, 1867, by Dr. 

 Gwyn Jeffreys. Extends also into the North Sea: St. Magnus Bay, 100 fathoms, 

 1867; 90 fathoms off North Unst, 1868; < Porcupine,' 1870: 795 fathoms (17 a) and 358 

 fathoms, Station No. 8; Galway Bay. ? 



It ranges to Norway. 



A similar form occurs in Canadian waters, and another in Japanese seas. 



The cephalic region (Plate C, fig. 15) ends anteriorly in a short, bluntly-conical peak. 

 The rim is more largely developed than in Praxillella prmtermissa, with a rather shallow 

 lateral notch on each side, and a median posteriorly. The median ridge begins a little 

 behind the middle and extends forward so as to embrace the peak, the whole thus having 

 the outline of a spoon, a feature not alluded to by Arwidsson. The nuchal grooves begin 

 about the middle of the head and diverge a little anteriorly. Eyes occur on each side of 

 the anterior peak. The proboscis in extrusion presents a longitudinally furrowed basal 



