On Dactylumys dactylinus and Kannabareomys amblyonyx

Dactylomys is the name of a genus of South-American Rats, created in 1838 by Mr. Is. Geoffroy-Saint-Hilaire ¹) for the reception of Echimys dactylinus of Mr. E. Geoffroy- Saint-Hilaire (1817). Mr. Is. Geoffroy bestowed the specific title typus on that animal and herein all the later authors ²) have followed him, although according the rule of priority it would have been more correct to retain the name given by Mr. E. Geoffroy and to call the animal Dactylomys dactylinus. But as it perhaps is a matter of euphony and as Is. Geoffroy’s name typus once had gained the victory I followed in my paper in the Notes from the Leyden Museum, 1887, p. 224, the bad example of my predecessors. Natterer brought home from his journeys in South-America two rats, described³) by Andreas Wagner, as belonging to the mentioned genus, under the name Dactylomys amblyonyx Natterer, with the following short diagnose: » Dactylomys supra flavus, nigro-adspersus, subtus pulchre ochraceus; unguibus dilatatis; cauda tota pilis vestita.” The named author published later on ¹) a more detailed description based upon the same type-specimens from Natterer’s collections. In that paper Wagner makes no mention of skull or dentition. The very exact description of the external parts ends with the following terms: » Natterer erhielt 2 Exemplare, Männchen und Weibchen, aus den Waldungen von Ypanema (Provinz San Paulo). Diese Thiere leben auf Bäumen, klettern sehr gut und tragen in Baumhöhlungen Vorräthe von Samen und Früchten für den Winter zusammen. Das Weibchen war mit einem Jungen trächtig.”