On a new IIippo.slclorii3/?v//i Borneo. 271 



already worn. All the clieck-teeth small, roiuidcfl, and appa- 

 n-iitly less high-crowned than usual; last molar particularly 

 small, little more than half the area in cross-section of m'. 



Dimensions of the skull : — 



Greatest length 85 5 millim.; basilar length 69; zygo- 

 matic breadth 42 ; nasals, greatest length (diagonally) 22"!5, 

 length to anterior notch 18, greatest breadth 11" 7, least 

 breadth 105; interorbital breadth 24; length of parietal 

 suture 7; interparietal 22xlil"3; breadth between outer 

 angles of anteorbital foramina 26 ; diastema 24'2 ; palate 

 length from henselion 35; length of upper cheek tooth- 

 series 15'2. Lower jaw : condyle to incisor-tip 51; height 

 to condyle 18"6; length of tooth-series V'yG. 



Uab. Lower Aruwimi River, close to its junction with the 

 Congo. 



Type. B.M. no. 2. 2. 28. 1. Collected and presented by 

 Capt. Guy Burrows. 



This interesting rodent is conspicuously different from 

 A. centralis J its nearest ally both zoologically and geogra- 

 phically, by its smaller size, smaller nasals, larger inter- 

 parietal, and the other details above described. 



XLV. — A new Ilipposiderus from Borneo. 

 By OLDFiiiLD Thomas. 



Ilipposiderus dyacorum^ sp. n. 



Allied to //. hicohr, with which (using the order of the 

 characters in Dobson's synopsis) it agrees in having | pre- 

 molars, no secondary leaflets on the sides of the muzzle, 

 frontal glands present, the front concave surface of the erect 

 leaf divided by three distinct ridges, and in size. Ears of 

 medium length, slightly surpassing when laid forward tho 

 tip of the muzzle ; their inner margins convex below, straight 

 above, the tip sharply defined, angular, the upper third of 

 the outer margin flatly concave, the lower part convex, with 

 an obtuse projection at its most convex point. Nose-leaf 

 small, its characters much as in //. biculor^ but the horseshoe 

 narrows forward more markedly, and tiie se[)tum between the 

 nostrils is not thickened. 



Anterior upper premolar minute, outside the tooth-row, the 

 large premolar pressed close up to the back of the canine. 

 Below the anterior premol.ir is also quite small, barely half 



I'J* 



