1903.] OF THE PERCY SLADEK EXPEDITION. 237 



no two can be found that are exactly alike, the set ranging in 

 colour from uniform red to nearly uniform black, and varying as 

 much in details as in general tone. The skulls also vary very 

 considerably both in size and in the development of their bullae, 

 the extremes appearing at first sight to be quite different species, 

 but being connected together by every gradation. 



17. SciURUS LANGSDORFFi Brandt. 

 ^. 1088, 1154, 1177, 1182, 1195. 

 $. 1081, 1124, 1155, 



A valuable series representing the true S. langsdorffi, which 

 name has been applied by various authors to many different 

 m-embers of the group, 



18. Rhipibomys roberti, sp. n, 

 c?. 1023, 1140. 



A Rhipidomys intermediate in size of skull between the large 

 species of the R. macrurus-latimamts group, and the small ones 

 allied to R, phceotis ; most nearly related to the latter. 



Fur of medium length ; hairs of back about 7-8 mm, in length. 

 General colour above dull fulvous or " clay-colour," finely lined 

 with black. Sides clearer and more buffy, bordered below by a 

 clear ochraceous-buff line edging the pure sharply-defined white of 

 the belly. Face like back, rather less heavily lined. Cheeks 

 buffy, like sides. Eyes without darker inngs. Ears of medivim 

 length, brown, not strongly contrasting with the general colour. 

 Outer side of arms and legs like flanks, inner pure white on the 

 fore limb down to the wrists, but on the hind limb only halfway 

 down to lower leg, the fulvous passing round the ankles ; hands 

 and feet dull whitish. Tail fairly long, rather less hairy than 

 usual in this genus, its basal inch furry all round and coloured 

 like the body ; the remainder vmiformly brown. 



Skull shaped most like that of R. benevoleus, although much 

 larger. Supraorbital ridges fairly well developed, evenly divergent 

 backwards. Outer plate of anteorbital foramen scarcely developed 

 anteriorly. Palatal foramina of medium length, narrow and 

 pointed anteriorly, broadly open posteriorly ; not reaching back 

 to the level of m.^ Interpteiygoid fossa of normal shape, with 

 rounded anterior border. 



Dimensions of the type, measured in flesh : — 



Head and body 110 mm.; tail 145; hind foot (s. u.) 25, 

 (c. u.) 26-7; ear 16. 



Skull — greatest length 32 mm. ; basilar length 24*5 ; greatest 

 breadth 16 ; length of nasals 11 ; interorbital breadth 5*6 ; breadth 

 of brain-case 14 ; length of palate 13*6 ; diastema 8 ; palatal 

 foramina 5 X 3'1 ; length of upper molar series 4*8 . 



Type. Adult d • B.M. No. 3.7.7.67. Original number 1023. 

 Collected 6 July, 1902. 



Although Mr. Robert's trunk measurement of the type of this 

 species is slightly less than that given by Mi'. Simons for R. phceotis, 



