200 MR. OLDFIELD THOMAS ON NEW [NoV. 3, 



some way behind m.^ Bullae but little swollen. Lower jaw 

 remarkably high anteriorly, the usual deep hollow in front of the 

 molars largely filled up. 



Incisors very peculiar in that while the upper ones are of 

 about normal breadth and depth, the lower are quite dispro- 

 portionally narrow and deep ; in most Rodents the upper and 

 lower incisors are of approximately equal transverse dimensions, 

 but here the two lower ones combined are of only the same 

 breadth in front as a single upper one, while in depth the lower 

 teeth exceed the upper by a third, and nearly resemble in shape 

 those of Bauhentonia. Their roots a.re carried unusually far up 

 at the back of the jaws, so that their basal inflation is at the 

 level of the yoke between the coronoid and condylar processes. 

 Molars very small, their length less than one-fifth the basilar 

 length, and the palate between them about twice their breadth. 

 Their laminae directly transverse, with simple raised enamel-edges 

 and concave dentine- spaces ; last lamina of m.^ and m.^ each with 

 a small additional internal ring inserted in front of it, the 

 homologue of a supplementary cusp ; lower molars with four, 

 three, and two simple laminae respectively. 



Type, Anisomys imitator. 



This genus seemed to be even less allied to any knov/n one 

 than Hyomys, and it could not be said what were its nearest 

 relations. Perhaps when young specimens were obtained, so 

 that unworn molars could be examined, some light would be shed 

 on this problem. In any case the genus might be readily 

 distinguished by the peculiar charactei-s of incisors and molars 

 above detailed. 



Anisomys imitator, sp. n. (Plate XXIII. figs. 1 «-l e.) 



Size and other external characters remarkably like those of 

 the large Vrotnys {U. validus or papimnus), with which it is 

 associated. Fur short and coarse ; hairs of back about 10-12 mm. 

 in length, unmixed with longer piles. General colour above 

 coarsely mixed blackish and fawn or buffy, the resulting mixture 

 approaching " mummy-biown " of Ridgway. Under surface dvill 

 buffy white, the hairs slightly darker at their bases. Head 

 rather more greyish than back, heavily lined with black. Eyes 

 surrounded by indistinct black rings. Ears of medium size, their 

 fine hairs blackish. Arms and legs dark grizzled grey, the 

 inner sides rather lighter ; hands and feet brown, becoming 

 whitish at the ends of the digits; claws rather delicate and 

 sharply pointed ; palms and soles naked, with large smooth pads : 

 fifth hind toe i-eaching nearly to the end of the first phalanx of 

 the fourth. Tail fairly long, set with medium-sized scales set in 

 alternating rows, and averaging about 9 to the centimetre ; very 

 thinly hairy, the short whitish hairs becoming rather longer 

 towards the tip ; its colour dark brown for its basal fourth, the 

 remainder yellowish white. 



Skull smooth and rounded ; nasals and premaxillary processes 



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