Hooks: 6-9; anterior teeth: 6-9; posterior teeth: 9-15.
Maximum adult body length: 30 mm; tail: 20-30 %.
Body needle-like and firm, opaque; transversal musculature absent; head fairly large; hooks serrated both in juveniles and in adults. Fin bridge absent. Anterior fins of medium length, reaching to posterior end of ventral ganglion, partially rayed, rounded; posterior fins long, partially rayed, rounded. Collarette absent or very small; gut diverticula absent. Small eyes with T-shaped pigment spot. Seminal vesicles with knob and trunk. Seminal vesicles with appendages. Position of seminal vesicles: between fins, nearly touching both when mature. Ovaries long, reaching anterior end of ventral ganglion; ova small. Adhesive papillae and adhesive organs absent. Apical glands absent.
Distribution: epipelagic; subantarctic and subarctic in the Antlantic, subantarctic in the Indo-Pacific.
Remarks: seminal vesicles with elaborate knob with numerous protuberances.
Type locality: South-Eastern Australia.