World Register of Marine Species (WoRMS)
Schuchert, P.; Choong, H.; Galea, H.; Hoeksema, B.; Lindsay, D.; Manko, M.; Pica, D. (2026). World Hydrozoa Database. Hippurella annulata Allman, 1877. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=290122 on 2026-08-24
Allman, G.J. (1877). Report on the Hydroida collected during the Exploration of the Gulf Stream by L. F. de Pourtalès, Assistant United States Coast Survey. Memoirs of the Museum of Comparative Zoology. 5: 1-66, plates 1-34.
Fewkes J.W. (1881a). Report on the Acalephae. In: Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Caribbean Sea, in 1878, 1879, and along the Atlantic coast of the United States, during the summer of 1880, by the U.S. Coast Survey Steamer Blake. Bulletin of the Museum of comparative Zoölogy of Harvard College. 8: 127-140, pls 1-4.