A mouse, collected by Mr. Bartels, April 1903, at an altitude of 6000 feet on the Pangerango-mountain, Java, was presented by that gentleman to our Museum. In comparing it with our Javan Mice I see that the animal differs enough to bestow it with a new specific title. Superficially it reminds my Mus lepturus, also from Java, however without more exact locality on that island ; especially striking is the very elongated fur of the upperparts, indicating their origin of elevated localities. I propose the name Mus Bartelsii, n. sp. The extremely soft hairs of the back of a dark mousecolor; each hair tipped with sooty black, towards the neck and bead and the sides the hairs are tipped with mahogany; posterior extremities and base of tail colored like back, anterior extremities like sides of body; underparts have the hairs of a mouse-color, tipped with pure white; hands and feet with short straw-colored hairs, on their basal parts a dark patch; tail basally blackish, passing gradually towards its (incomplete) end into a yellow tinge; hairs of tail extremely short, scales very small, smaller than in lepturus. Ears much shorter than in the latter species, rounded at the tip, about as broad as long. As with trapped small animals generally, the skull has posteriorly been smashed, so that its length cannot be given.