Umbonium mysticum Yokoyama
| 1923. | Umbonium mysticum Yokoyama |
| Condition: | Present |
| Taxonomy: | Mollusca: Gastropoda: Trochidae: |
| Geologic Time: | Cenozoic: |
| Yokoyama, M., 1923b: Tertiary Mollusca from Dainichi in Totomi. Journal of the College of Science, Imperial University of Tokyo, vol. 45, art. 2, pp. 1–18, pls. 1–2. (Reference No. 0468) |
  |
| Ichikawa, T., 1983, no. 9, p. 292. |
