World Register of Marine Species (WoRMS)
WoRMS (2026). Orcula cucumiformis Semper, 1868. Accessed at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=214676 on 2026-08-30
Semper, C. (1867-1868). Holothurien. In: Semper, C., ed.: Reisen im Archipel der Philippinen. Zweiter Theil. Wissenschaftliche Resultate. Erster Band. Leipzig: W. Engelmann. iv + 288 pp., 40 pls. [1867 = pp. 1-70, pls. 1-15; 1867/(1868) = pp. 71-100, pls. 16-25; 1868 = pp. 101-288, pls. 26-40].