Bornean Species of the Genus Mus. 455 



length of the head and body, thinly haired, the scales large 

 and prominent, about eiglit to the centimetre ; bicolor slaty 

 grey above, white below, and commonly at the end all round 

 for an inch or two ; no terminal tuft of hairs. 



Skull strongly built, with a broad heavy muzzle. Frontal 

 region remarkably flattened, even concave in old specimens ; 

 supraorbital ledges very strongly developed, overhanging the 

 orbits, and forming marked postorbital angles, behind which 

 they run back to the antero-external angles of the inter- 

 parietals. Anterior edge of interparietal approximately 

 transverse. Plate of zygoma but little developed, its anterior 

 edge vertical. Palatal foramina short, widely open, their 

 posterior limit two or three millim. in front of ^. 



Teeth rather small in proportion to the size of the skull. 



Hind foot of the typical skin ( (J ) 39 millira. 



Dimensions of an adult male in spirit (from Paitan, N. 

 Borneo) : — 



Head and body 196 millim. ; tail 196; hind foot* 37-5; 

 ear 22 x 16 ; heel to front of last foot-pad 19"5. 



Hah. (of type). Mount Batu Song, Barara district, Sara- 

 wak. Coll. A. H. Everett, Oct. 1891. 



Type: B.M. 92.9.6.15. 



M. rajah is the species which I have hitherto looked upon 

 as M. Hellwaldij Jent., and it is mentioned under this name 

 both in my own papers and in Hose's ' Mammals of Borneo.' 

 I still regard it as closely allied to M. Htllwaldi^ which was 

 described from Celebes ; but, in view of the entire spineless- 

 ness of the three Celebean specimens I have seen, and the 

 uniform spininess of the sixteen Bornean ones before me, of 

 all ages and seasons, I am compelled to consider this character 

 of sufficient constancy to demand the specific distinction of 

 the latter from the former. 



Some specimens of this species have a rufous or greyish 

 collar dividing the white of the chin from that of the chest, 

 and this is especially noticeable in immature individuals. 

 Kina Balu examples have this collar at a maximum, but 

 further skins are needed before the local constancy of the 

 character can be proved. An immature specimen from the 

 Penrisen Hills and another from Bunguran both have collars, 

 while other examples from the same localities are without 

 them. 



* Although a good typical representative of the ordinary lowland form 

 of M. rajah, this specimen has unnaturally swollen and probably shortened 

 feet. The hind foot of another spu'it-specimen, from Palawan, is 

 40 millim. ; heel to front of last foot-pad 20, 



