Key to species of Amphisamytha:

1. Eye-spots present. One pair of anal cirri present .......................................................................................................... 2

- Eye-spots absent. Anal cirri absent............................................................................................................................... 3

2. 2 eye-spots present. Abdominal glandular pads with dorsal cirri. Teeth of uncini in 2–3 vertical rows .... A . bioculata

- Numerous eye-spots present. Abdominal glandular pads without dorsal cirri. Teeth of uncini in 1 vertical row ......... .................................................................................................................................................................... A . japonica

3. Up to 25 abdominal segments. Abdominal glandular pads with dorsal cirri.......................... A. vanuatuensis sp. nov.

- Up to 15 abdominal segments. Abdominal glandular pads without dorsal cirri.................................. A. galapagensis