390 MR. J. L. BONHOTE ON THE [NoV. 28, 



Mus plumbeus A. M.-E. Rech. Mamm. p. 138, pi. 43. lig. 2 

 (1874). 



Mils rattus fiavifpectus A. M.-E., Thos. P. Z. S. 1898, p. 772. 



This species is the representative of the rufescens-^-ovc^ of 

 Mus rattus, which inhabits China. It is of moderate size, having 

 the tail rather shorter than the head and body. Fur soft and 

 destitute of spines. General colour above uniform yellowish 

 brown, slightly lighter on the flanks. Hairs slate-coloured at 

 their base, with ochreous tips, and intermixed among these are pure 

 black hairs of a finer texture. Under parts varying from dirty 

 yellowish to yellowish-white, often, but not invariably, showing- 

 traces of a white mark on the breast. The hind feet are whitish 

 and the hands dark brown margined with white. Tail unicoloured 

 and covered with hairs. 



Skull. The skull is that of a fairly typical Mus rufescens, and, 

 except in its slightly smaller size, is indistinguishable from the 

 Indian form*. 



Dimensions. Head and body 200 mm. ; tail 160 ; hind foot 31 ; 

 ear 18. 



Skull t. Greatest length 41 mm. ; basilar length 36-5 ; j^alatilar 

 length 20 ; diastema 11*5 ; length of incisive foramina 8 ; length 

 of nasals 15; zygomatic breadth 20; interorbital breadth 6; 

 breadth of brain-case 15"5 ; length of molar series 7. 



Habitat. The type of this species came from Moupin in 

 W. Szechuen, but it also occurs at Kuatun in N.W. Fokien, 

 Kiou Kiang in Kiangsi, and Foochow, so that it is probably 

 widely distributed throughout the country. It also occurs in 

 Formosa. 



This and Mus griseij^ectus are the common Rats of China. The 

 diiference in the colour of the luider parts, as denoted in their 

 specific names, will form to some extent a distinguishing character, 

 although the under j)arts in Jiavipectus often become very light, 

 and in old specimens of g7'iseipectus may show a yellowish tinge. 

 However, I am inclined to think this character unreliable, and 

 a much better test is the greater size of griseijiectus, as shown by 

 the leng-th of the hind foot and skull-measurements. In grisei- 

 pectus^ moreover, the tail, although it can hardly be called 

 " bicolor," is distinctly lighter on its under surface, and this seems 

 to be the only reliable external characteristic at all ages. 



In the description of M. Jiavipectus in the Rech. Mamm., 

 M. Milne -Edwards adds a footnote to say that M. germaini from 

 Pulo Condor closely resembles this species, especially in its 

 coloration. Although a^Dproximately correct, it may be well to 

 notice that M. germaini may be distinguished by its size, which 



* For cavoful figure of the skull of 31. rrifescens, see paper by the author, 

 Fasc. Malayeuses, Zoologj% vol. i. pi. iv. fig. 3 (1903). 



t The measviretnents, which are the same as those taken in my former paper, are 

 now called after Mr. 0. Thomas's scheme for cranial measurements, published 

 Proc. Biol. Soc. Wash. vol. xviii. p. 191 (1905), the alterations (in name only) being 

 basilar and palatilar for basal and palatal. 



