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DESCRIPTIONS OF TWO GIANT RATS FROM NEW GUINEA, 

 PRESENTED TO THE BRITISH MUSEUM BY THE HON. 

 WALTER ROTHSCHILD, F.R.S. 



By OLDFIELD THOMAS. 



(Published by permission nf the Trustees of the British ifuseuui.) 



Uromys rothschildi sp. n. 



A very large. wholly black-tailed species allied to U. anak. 



8ize rather less than in U. anak. General colour above blackish grey, 

 appearing at first sight mnch darker than in anak, but this would seem to be due 

 to the fact that the type is almost wholly in fresh unbleached pelage, while that 

 of anak is, with the exception of a few patches, in a bleached and reddened 

 condition. These few patches are, as stated in the original description, of a dark 

 grizzled grey, made up of mixed black and white, and this colour is closely similar 

 to that of U. rothschildi ; the latter appears, however, to be rather more heavily 

 washed with black on the crown and fore-back. Under-snrface dull soiled whitish, 

 not sharply defined laterally, the basis of the hairs pale slaty, except on the throat 

 and a small patch on the middle of the chest, where they are white to the roots ; 

 chin dark brown. Ears short, rounded, naked, brown. Hands and feet blackish 

 brown above, the digits practically naked. Tail with its basal two inches hairy, 

 blackish ; the remainder naked, finely scaled, black to the tip. Mammae, — 2 = 4. 



Skull essentially rather smaller than that of U. anak, but owing to its 

 longer muzzle the total length would be about the same. Nasals very long, 

 narrow, their broadest point in front, then narrowing and again broadening at their 

 middle ; not extremely narrowed behind. Supraorbital edges well ridged ; a 

 prominent sub-postorbital process present. Diastema very long, with the palatal 

 foramina situated far forwards, their posterior end in front of the anterior end of 

 the anteorbital canal ; the distance from their hinder end to the front root of m' 

 decidedly greater than that from their front end to the henselion. Molars smaller 

 than in U. anak. 



Dimensions, taken on skin : Head and body, 350 ; tail, 355 ; hindfoot (wet), 

 68; ear (wet), 23. Skull, gnathion to basilar suture, 58 ; zygomatic breadth, 34; 

 nasals, length, 28, anterior breadth, 7-4, middle breadth, ()-5 ; interorbital breadth, 

 10-5; breadth between parietal ridges, 18-2; height of muzzle behind incisors, 

 14-2; height of crown from alveolus of m', 19"5 ; palatilar length, 37-0 ; diastema, 

 23 ; palatal foramina, 6-5 x 3-4; upper molar series (crowns), 12-8. 



Hab. : Rawlinson Mts., S.E. German New Guinea. 



T>j/jc: Adult female, B.M. No. 12. 1.31.2. Collected by C. Keyser, and 

 presented by the Flon. Walter Rothschild, F.R.S. 



This fine species, which 1 have named in honour of the donor of the two 

 valuable rodents now described, is undoubtedly most nearly allied to U. anak, but 

 differs by the cranial details above described. U. ralidiia and the other related 

 New Guinea sjiecies are smaller, and have yellow tail-tips. U. miiltijdicatas Jent., 

 a species based on a young specimen, came from Humboldt Bay, and is therefore 

 not likely to be the same. All this group of Uromi/s have the "multi-plicate" 

 structure of tlie palate used as a distinguishing character by Dr. .Tentink. 



