LUMBRICONEREIS HIBERNICA. 383 



4. Lumbriconereis hibernica, n.s. Plate LXII, figs. 3 and 3 a — lie ad ; Plate LXXIV, 

 figs. 1 and la — feet; Plate LXXXII, figs, b-b d — bristles. 



Specific Characters. — Head forms a somewhat narrow cone with a pointed apex. 

 Body typical; the bristles, however, approach those of L. impatiens in length. Posterior 

 lobes of feet not elongated. Maxillae normal; great dental plates with four teeth. Two 

 lateral plates simple. Mandibles with somewhat elongated anterior plates, the edges of 

 which are crenate. First foot with three or four pale spines, and two groups of tapering 

 winged bristles. The tenth foot has four pale spines and a short conical posterior lobe. 

 Dorsally are winged tapering bristles, whilst below the spines are characteristically 

 tapered simple hooks — indicating how easily such could merge into a tapering bristle. The 

 tips of these gradually shorten, so that at the twentieth they are, proportionally, only 

 half the length. At the thirtieth foot they have short tips and broad wings, and this 

 condition continues to the sixtieth, in which, as in the thirtieth, the lobes of the feet are 

 nearly equal. 



Synonym. 

 1903. Lumbriconereis hibemica, Mcintosh. Ann. Nat. Hist., ser. 7, vol. xi, p. 561. 



Habitat. — Dredged in ninety fathoms, twenty-five miles west of the Blasquet, S. W\ 

 Ireland, May, 1869 (Dr. Grwyn Jeffreys) ; in the same region (log 55) in twenty-three to 

 thirty-eight fathoms, P. I. A. Exped., 1886. 



Head (Plate LXII, fig. 3) forms a somewhat narrow cone with a pointed apex, and a 

 slight median groove on the ventral surface. 



Body of the normal outline, tapered for a short distance anteriorly, and more 

 distinctly so posteriorly. The first segment is rather broader than the second, and the 

 glistening bristles are more conspicuous than usual, in this respect approaching Lumbrico- 

 nereis impatiens. So far as can be observed in the examples the feet do not present the 

 elongated posterior lobe so characteristic of several forms, but none are complete 

 posteriorly. The segments after the twentieth have a tendency to increase in breadth, and 

 the posterior are about twice the breadth of the anterior. Reproduction of the posterior 

 end takes place readily, a miniature tail sprouting from the last segment, and showing 

 the four cirri at the tip. 



The great size of the dorsal longitudinal muscles and the arrangement of the oblique 

 muscles, which pass below the nerve-cord, are noteworthy (Fig. 79). 



Proboscis.— In an extruded organ (Plate LXII, fig. 3 a) the maxillae occupy the 

 anterior and central region of the bilobecl organ, their action being lateral, that is, each 

 working in and out from its own side. The great dental plates are behind them, their 

 four prominent teeth projecting on each side of the central space in front and slanting 

 inward to the posterior part of the plates. The two lateral plates extend outward on 

 each side, so that an elongated transverse dental series is formed in this position. The 

 mandibles with their double curves and median fissure project a short distance behind, 

 the cutting edge being bare. 



So far as can be observed the food would be seized by the maxilla? and lacerated by 



