548 MESSRS. THOMAS AND WROUGHTON ON [May 26, 



Hah. Tette, Portuguese Zambesia. 



Type. Adult female. B.M. no. 8.4.3.79. Original number 

 1980. Collected 27th August, 1907. 



Outwardly this species has a most striking resemblance to 

 M. naniaquensis, but its skull and teeth characters separate it. 

 readily from any member of that group. The shape of the skiill 

 and large size of the teeth point conclusively to its close affinity 

 to M. chr7/so2)hih(,s, of which it is no doubt a dwai'f form. 



[Mus ARBORARius Peters. 



As this species was based on specimens from Tette we have 

 given special attention to its identification. Peters in his 

 description* mentions two specimens, but as he quotes the 

 dimensions of the female in the diagnosis and figures its skull 

 (that of the male being still in the stuffed specimen t) we adopt it 

 as the type. He gives an excellent figure of the skull {I. c. 

 pi. XXXV. fig. 7), and. this agrees in all essential characters with 

 that of a specimen from Salisbury, Rhodesia, belonging to a 

 widely-spread species, of which we have been able to recognise at 

 least four local races, as follows : — 



1. Mus NAMAQUENSis Sm. Hctb. Namaqualand. (= " Mies 



auricomis de Wint.," Thos. & Schw. P. Z. S. 1904, p. 179.) 



2. Mus NAMAQUENSis CENTRALIS Schw. Rcib. Deelfontein, O.C. 



(^=zMus auricomis centralis Schw. P. Z. S. 1906, p. 107.) 



3. Mus NAMAQUENSIS liEHOCLA Sm. Hah. Kuruman. [= Mus 



lehocla Sm. Type locality " Latakoo.") 



4. Mus NAMAQUENSIS AURICOMIS de Wint. Hah. Mashonaland. 



{=Mus auricomis de Wint. P. Z. S. 1896, p. 802.) 



We have unfortunately no material to enable us to judge 

 whether arhorarius is identical with the Mashonaland race or 

 whether, as seems to ns more probable, it forms a fifth geo- 

 graphical subspecies. 



This identification altogether removes arhorarius from the 

 Thamnotny^ group, to which it has been usually referred, perhaps 

 on the evidence of the stuffed male, which may possibly prove to 

 be an example of the next species. 



The skull of Mus namaquensis has, as Peters's figure of 

 " arhorarius " shows, evenly divergent suj)raox'bital ridges, cut 

 back anterior' zygomatic plate, small bullse, and comparatively broad 

 parapterygoid fossae, all these characters being in contrast with 

 those shown by the Tette Thamnomys next to be described. 



The definite determination of the old types of Smith's Gerhillus 

 naniaquensis and 3Ius lehocla is one of the many advantages 

 gained from the study of the Rudd Collection.] 



* Reis. Mossainb. p. 152, 1852. 



t At least when Thomas examined it in Berlin in 1887. 



