Imprint date 1886, but treated as 1887 in Hartman bibliography & catalogue, perhaps arising from a mistake in Ditlevsen 1917:39 (Ingolf) who uses 1886 in one place and 1887 in another. There is no evidence from elsewhere that publication was not until 1887.
Levinsen, G. M. R. (1886). Kara-Havets Ledorme (Annulata). [Book section]. 288-303. plate 25. IN: Lütken, C. F. (Ed.). Djimphna-Togtets Zoologiske-botaniske Udbytte. J. Hagerup. Köbenhaven.