174 MR. OLDFIELD THOMAS ON 



and also into the seventh, the anterior space, which is curved 

 inwards to form a fifth internal angle, while there are only three 

 external angles ; the tooth is thus very like that figured by 

 Biichner in M. limnophilus (Mamm. Przewalsk. pi. xviii. fig. 13). 



Dimensions of the type : — 



Head and body 98 mm. ; tail 37 ; hind foot 18 ; ear 13. 



Skull : condylo-basal length 24-2 ; basilar length 22 ; greatest 

 breadth 14-8 ; nasals 7 ; interorbital breadth 3'8 ; breadth of 

 brain-case 12 ; height of forehead from alveolus of m" 7 ; palatilar 

 length 13; palatal foramina 4-8 ; diagonal diameter of bulla in 

 horizontal plane 6'5 ; upper molar series (crowns) 5-7. 



Hah. as above. 



Type. Old female, B.M. No. 11.2.1.195. Original number 2396. 

 Collected 2 July, 1910. 



This species is peculiar for the proportionately small size of its 

 brain-case and its narrow interorbital space. From M. limnophilus 

 Biichn., which may possibly be allied to it, it is distinguishable by 

 having only three internal angles on m^ ; the shape of the brain- 

 case would also seem to be more normal in that animal. 



36. MiCRO TUS MALCOLMI. 



Thos. Abstr. P. Z. S. 1911, p. 5 (Feb. 14). 



S. 2245, 2250, 2251, 2252. $. 2246, 2253, 2254, 2255, 

 2256, 2257. Mts. S.E. of Tau-chow, Kan-su. 



A medium-sized Yole with high arched skull, somewhat similar 

 on a smaller scale to that of M. ccdamorum Thos. 



Fur soft and fine, of medium length ; hairs of back about 

 9-10 mm. in length *, therefore conspicuously shorter than in 

 Proedromys. Colour above lined brown, rather lighter than 

 " bistre " ; under surface washed with greyish white, rather 

 mai-kedly contrasted with the upper colour. Ears slightly 

 projecting from the fur, brown. Upper surface of hands and feet 

 dull whitish ; soles with six pads. Tail rather more than double 

 the length of the foot, brown above, dull white on sides and 

 below. Mammee apjjarently 2 — 2 = 8, but this cannot be made out 

 with certainty. 



Skull rather like that of M. ccdamorum on a small scale, 

 though not so strong and heavily ridged. In general shape it is 

 not tiattened above, but high, arched above, the nasal profile 

 bowed downwards, the waist narrow and proportionately far 

 forward. Surface everywhere smooth and unridged ; squamosal 

 projections scarcely perceptible. Nasals nearly attaining to the 

 level of the premaxillse behind. Interorbital space narrow, 

 smooth, evenly convex above, not flattened or hollowed mesially. 

 Brain-case smoothly rounded. Palatal foramina of equal breadth 

 throughout, their length exceeding that of m^^-m^ Posterior 

 palate with very deep lateral pits and unusually narrow meso- 

 pterygoid space. Bullae decidedly larger than the normal. 



* In tliis measurement I alwaj's ignore tlie outstanding tips of the longer liairs, 

 and only measure to the ends of the thick mass of under-fur. 



