Brinkmann, 1915
Body widest anteriorly, gradually narrowing posteriorly; after preservation length 20.5 mm, width 8.5 mm, thickness 4.5 mm, but Coe (1926: 116) comments that "The worm in life was doubtless much flatter . . . for the figures . . . show that the dorsal musculature was violently contracted during preservation"; Van der Spoel's (1985) example was 13 mm long and 6 mm wide; 24 proboscis nerves; rhynchocoel nearly as long as body (Van der Spoel, 1985, states two-thirds of body length), with wall containing interwoven meshwork of circular and longitudinal muscle fibres; stylet armature a sickle-shaped basis bearing very small stylets; mouth and proboscis according to Coe (1926: 116) "open together in a single atrium", but Van der Spoel (1985: 17) states "Mouth and proboscis pores separate"; intestinal caecum with 5 pairs of branched diverticula, intestine with numerous diverticula, each with dorsal and ventral lobes; female with 14 pairs of ovaries; males unknown.
Distribution: The original specimen was taken in a vertical haul between 3000 m and the surface, but a second individual identified as belonging to this species came from 515-995 m depth. Known from the South Atlantic (west of the Cape of Good Hope) and North Atlantic (approximately mid-way between the Canary Islands and the Mid-Atlantic Ridge); anatomical differences recorded between the North and South Atlantic records suggest that the North Atlantic form may not belong to this taxon.