EEPORT ON THE ANNELIDA. 
197 
between the eyes, and it and the antennse are long, slender, and moniliform. The 
pharyngeal region is extruded, as in the foregoing form, but its colour is dusky greyish, 
and it is not so horny. The palpi (frontal lobes) form two large, bluntly conical, 
flattened organs projecting from the snout. 
The feet are furnished with longer bristles than in Syllis setubalensis. The dorsal 
cirrus (PI. XXXIII. fig. 7) is more decidedly tapered from base to apex, and has a 
variable number of segments, generally about forty-four. The setigerous division is less 
rounded at the tip, and anteriorly is supported by a single strong spine, the tip of which 
is dorsal. There are .about four stoutish bristles beneath it, each with a minute yet dis- 
tinctly bifid terminal appendage (PI. XVa. fig. 20), while the distal end of the shaft 
has a small style. The whole appearance is such as might be expected from a further 
development of the form seen in Syllis setubalensis. The bristles retain the same 
characters in the posterior region of the body (which is more complete than in the 
previous species), so that there is an evident distinction between them in this respect. 
The ventral cirrus is shorter than in Syllis setubalensis, and does not reach a vertical line 
from the tip of the setigerous division. It is also less inclined upward at the tip, and 
posteriorly becomes even less prominent. 
This species approaches certain forms of Eusyllis in regard to the terminal pieces of 
the bristles, but at the same time these appendages are much shorter than any known 
example. The terminal pieces also differ considerably from those of Syllis gracilis, 
Grube. 
Syllis robertiancB, n. sp. (PL XXXIV. figs. 1,2; PL XXIXa. fig. 14). 
Habitat. — Trawled at Station 320 (off the coast of Buenos Ayres), February 14, 
1876 ; lat. 37° 17' S., long. 53° 52' W.; depth, 600 fathoms; bottom temperature 37°'2, 
surface temperature 6 7° ’5 ; sea-bottom, green sand. It was in an incrusting Sponge on 
the tube of Pista mirabilis. 
The specimen is 13 mm. in length, and fully 1 mm. in diameter anteriorly. 
The body tapers gradually from before backward. The head is elongated transversely, 
the antero-posterior diameter being very short. The palpi are bluntly conical when 
viewed from the dorsum, and ventrally present the usual bulbous extremities. There are 
four eyes, situated along the arms of a very wide V. The anterior pair are much farther 
apart, are twice as large as the posterior, and quarter moon-shaped, the concavity being 
in front. The posterior pair are circular. The median and anterior tentacles are about 
the same length, and all are evidently articulated as well as very fragile. The tentacular 
and dorsal cirri are, like the former, elongated, about forty-one or forty-two articulations 
occurring in the dorsal. These organs are gradually tapered from base to apex. 
