Mammals from South Africa. 461 



The dimensions of the type of M. chrysophilus de Wint. 

 are : — 



Head and body 146 mm. ; tail 168; hind foot 28 ; ear 19. 

 Tzaneen, Zoutpunsherg District, Transvaal (2500 feet). 

 Type S- 1-14. (ii.M. no. 9. 7. 2. 15.) 

 Caught 7th July, 1907. 



(23) Mus nomaquensis monticularisy subsp. n, 



Joliannesburg, Transvaal. 



Series. 



Wonderfontein Caves, Potchefstroom District, Transvaal. 

 ? (uimumbered). 



On comparing a series of some two dozen skins and half a 

 dozen spirit-specimens of this " golden rat," which 1 collected 

 on the kopjes of the Witwatersrand around Johannesburg, 

 with the material in the Biitish Museum, on which Thomas 

 and Wroughton based their revision of the Mus namaquensis 

 group (P. Z. S. 1908, p. 548), I tind that it is necessary to 

 create a new subspecies for the form occurring in the Southern 

 Transvaal. 



JJescription. — Colour between that of 2fus namaquensis 

 ti/picus and 2fus namaquensis auricomus, slightly browner 

 than the former and less rufous than the latter. Belly 

 white, with slate-coloured bases to the hairs ; these bases 

 are darker than in any other form except Mus namaquensis 

 centralis. 



Slightly larger than any of the other forms. 



Dimensions (of the type) : — 



Head and body 120 mm. ; tail 157; hind foot 26 ; ear 20. 



The tail is rather shorter in proportion to the head and 

 body than in the other forms, the ratio of the length of the 

 head and body to the length of the tail being about 10 : 12, 

 while the corresponding ratio in other forms varies from 

 10:13 to 10:14. 



Tail-rings 11 tj the cm. 



Young examples are browner and less golden in colour than 

 adults. 



Type $ (unnumbered). B.M. no. 9. 7. 2. 10. Johannes- 

 burg, 20th May, 1907. 



This species is essentially a rock-rat, and is by far the 

 commonest rat on the stony kojjjes around Johannesburg. 



It makes its nest (of grass, leaves, cfec.) in clefts in rocks 

 or in holes under boulders. 



I have never found this species away from rocky ground, 

 whereas the allied M, chrysop/iilus is a veld-rat, especially 



