250 
THE VOYAGE OF H.M.S. CHALLENGER. 
This species is distinguished from the Lumbriconereis {Notocirrus) splicer ocei^halus of 
Schmarda,^ from Auckland, New Zealand, by the shape of the head, the structure of the 
feet, and the bristles. In Schmarda’s form the foot bears a short cirrus, and thus the 
divergence is pronounced. 
Lumbriconereis abyssorum, n. sp. (PL XXXVI. figs. 20, 21 ; PI. XVIIIa. fig. 10). 
Habitat. — Trawled at Station 298 (olf the west coast of South America, a little south 
of Valparaiso), November 17, 1875 ; lat. 34° T S., long. 73° 56' W.; depth, 2225 fathoms ; 
bottom temperature 35°‘6, surface temperature 59°'0 ; sea-bottom, blue mud. 
Fig. 16. — Maxillce and dental plates of Lumbriconereis abyssorum; x 90 diameters. The position of the maxill® in this 
figure prevents the curvature being seen. The right anterior dental plates are flattened out. 
Fig. 17. — Tip of one of the maxillae of Lumbriconereis abyssorum, so as to show the curvature ; x 90 diameters. 
Fig. 18. — Mandibles of Lumbriconereis abyssorum ; x 90 diameters. 
A fragmentary example, measuring about 24 mm. in length and about 2 mm. in 
breadth anteriorly. 
So far as external appearance goes, this abyssal form differs little from a specimen of 
Lumbriconereis fragilis of the same size, except in regard to the structure of the lamellae 
of the anterior feet. 
The head (PL XXXVI. fig. 20) is somewhat larger and broader, but the mouth and other 
parts do not present any noteworthy difference from the common form just mentioned. 
The dental apparatus (Fig. 16) is brownish, with darker touches. The maxillae in 
the contracted condition of the included proboscis have their hooked tips (Fig. 17) directed 
upwards. The spathulate appendages posteriorly are broad, each approaching a semicircle. 
The left great dental plate has four teeth, the right four, but the two median are separated 
1 Neue wirbell. Thiere, I. ii. p. 116. 
