This picture is extracted from "Leche 1886 plate 16.png"; fig. 13. It shows the skull and the upper jaw of the Delomys dorsalis.
Wilhelm Leche (d. 1927, <a rel="nofollow" class="external autonumber" href="http://www.vethist.idehist.uu.se/Newsletter_pdf/NewsL_34.pdf">[1]</a>).
1886
Plate 16 from Leche (1886, Zool. Jahrb. 1, heft III/IV, pp. 687–702) reproduced in Musser, Carleton, Gardner and Brothers (1998, Bull. Am. Mus. Nat. Hist. 236, fig. 137).