260 A Subdivision of the Genus Uromys. 
XXIX.—A Subdivision of the Genus Uromys. 
By OupFieLp THOMAS. 
(Published by permission of the Trustees of the British Museum.) 
THe genus Uromys, which ranges from the Moluccas through 
New Guinea and the Solomon Islands to North Australia, 
has long been known to fall naturally into two very distinct 
groups. These have been by myself spoken of as the large 
species allied to U. macropus and the small ones allied to 
U. bruijnii. Now, however, in connection with the working 
out of some New Guinea mammals, I have had occasion to 
examine them more closely, and find that the differences 
are such that these groups may very well be treated as genera. 
In addition, the remarkable species U. sapientis of the Solomon 
Islands would seem also to deserve generic separation. 
The three genera may be distinguished as follows :— 
A. Skull with projecting zygomatic plate. Bullee 
very small, little inflated. Mesopterygoid fossa 
broad anteriorly, the palatal edge level with or 
behind m’. 
a. Size large, hind foot 52 mm. and upwards, 
skull-length 60 mm. and upwards. Tail 
long, commonly with contrasted white tip. 
Palatine foramina very short, their length 
not more than the distance from their hinder 
end tom’. Back of palate behind level of 
hinder edge of m°. Incisors very deep in 
proportion to their breadth, the depth of the 
lower ones equalling the combined breadth 
of the pair. Palate-ridges, where known, 
consisting of a large number (12 or more) of 
fine interdental ridges *, besides the usual 
predental ridg@osts cis. 2 ates ewes eelneiee mete I. Uromys, Peters. 
Synonym: Gymnomys, Gray. 
Genotypes of both names: U. macropus t, Gray. 
Range: New Guinea, Aru Islands, and N. Queensland. 
Species described: anak, aruensis, macropus, multiplicatus, nero, 
papuanus, rothschildt, scaphax, validus. e 
é, Size smaller, the largest with hind foot 45 mm. 
and skull 51 mm., but the majority far 
smaller. Tail usually shorter than in 
Uromys, though oceasionally long, either 
wholly black, or lighter below, but not known 
* As figured by Jentink, ‘ Nova Guinea,’ v. pl. xvi. fig. 6. 
+ Palmer erroneously gives celebensis as the genotype of Gymnomys ; 
but a reference to P. Z. 8. 1867, p, 597, paragraph 5, will show that the 
genotype is “ Mus maeropus.” 
