1905.] MAMMALS OP CHIXA. 393 



Tlie common Norway Rat occurs not infrequently in China, 

 as shown by several examples in the British Museum. Apart 

 from the skull-characters, which are quite distinctive, it may be 

 recognised from griseipechcs, which it reseinloles most closely 

 externally, by its larger size (hind foot 36 mm.) and stouter tail. 



MUS HUMILIATUS (A. M.-E.). 



Mits hitmiliatics A. M.-'E., Ann. Sci. Nat. vii. p. 375(1867); 

 id. Rech. Mamm. p. 137, pi. 41. fig. 1 (1874) ; Rhoads, Proc. Acad. 

 Nat. Sci. Philad. 1898, p. 121 ; Thos. P. Z. S. 1898, p. 772. 



Another member of the JIas rattus group but smaller. General 

 colour above yellowish-brown. Fur slate at its base, but yellowish 

 broAvn (cinnamon, Ridgw.) for the greater part of its length, 

 becoming paler on the flanks ; inteimixed with the fur are a few 

 long soft black hairs, but they are so scattered as to have but little 

 effect on the general coloiir. The hands and feet are white, and 

 the under parts uniform grey. The tail is shoi^t, tapering, and 

 bicoloured, well clothed with short hairs that are brown on the 

 upper and white on the lower surface. The ears small and 

 rounded and covered with fine hairs. 



The skull differs from that of 31. griseqyectus in being broader 

 and shorter. The supraorbital ridges are not so well marked and 

 do not run back so far, disappearing about halfway across the 

 parietals. 



Dimensions (taken in flesh : Nankin *). Head and body 

 145 mm. ; tail 115 ; hind foot 30 ; ear 16*5. 



Skull (of co-type). Gi-eatest length 35 mm. ; basilar length 29 : 

 palatilar length l7 ; diastema 7 ; length of incisive foramina 

 6; length of nasals 12; zygomatic breadth 18; interorbital 

 breadth 6 ; breadth of brain-case 15 ; length of molar series 7. 



Habitat. Pekin and neigbourhood (type); Nankin and W, 

 Fokien. 



The chief distinctive feature of this Rat is its light colour, caused 

 by the almost entire absence of the longer black hairs found in so 

 many species, and besides this its smaller size and short tail form 

 a combination of characters enabling it to be easily recognised. It 

 is apparently a scarce animal, as only one specimen has reached the 

 British Museum during the last 23 years, and it is entirely absent 

 from the collections of Messi'S. Styan, Rickett, and La Touche. 

 Mr. HoAvell has, however, just sent over a small collection, which 

 contains a mature female, from the city of Nankin, this specimen 

 agreeing closely in all respects with the type. 



A specimen received originally from the Paris Museum as 

 belonging to this species, and collected by Pere David in W. Fokien, 

 is undoubtedly Mies novegicus, and it was this example that led 

 Mr. Thomas to suggest Mios hihmiliatus as the possible wild stock 

 of Mus norvegicus. 



* The skull-measurements of tliis specimen practicallj' coincide with those of the 

 co-type. 



27* 



