"Genus Cossura Webster and Benedict, 1887
Cossura abyssalis, new species
Record: 1:19 sta. 333 (9, TYPE).
Description: All specimens are incomplete ; the largest is a fragment, measures 4 mm long by 0.5 mm wide and consists of 23 setigerous seg‑ ments. The prostomium is bluntly rounded in front, widest in back and its length is about equal to its width; eyes are absent. The first two segments are complete, asetigerous rings with the first one only half as long as the second one and together about as long as the first setigerous segment. The third segment has neuropodia with setae, but no notopodia. The fourth segment is the first biramous ; it has a pair of small notopodia and larger neuropodia.
Typically the setae are in spreading fascicles, with a shorter anterior and a longer posterior series ; all setae are narrowly limbate and smooth along the cutting edge.
The median tentacle is inserted mid-dorsally on the anterior end of the third setigerous segment ; it is smooth and widens distally.
Cossura abyssalis is unique in having setae first present from the third segment, and the median tentacle inserted on segment five. The first parapodial segment is uniramous. C. abyssalis comes nearest to C. laeviseta Hartmann-Schroeder (1962 b, p. 140) from Peru ; the latter has prostomial eyes ; and the median tentacle is inserted on the fourth [third setigerous] segment.
Distribution: Off Valparaiso, Chile, in 3655-3651 m. "
(Hartman, 1967)
