550 MR. O. THOMAS ON MAMMALS FROM NYASSALAND. [NoV. 1, 



known, and show such extremely slight differential characters, that 

 it is at present almost impossible to saj^ whether G. afer. Gray, 

 G. montanvs, Smith, G. leucogaster, Peters, G. boehmi, Noack, and 

 G. vcdidus, Boc, are all or any of them worthy of specific distinction. 

 Much larger series from different localities will be needed before ib 

 is possible accurately to work out this difficult group, and in the 

 meanwhile I use the earliest name available. In any case these 

 Nyassa specimens are so closely allied to the ordinary South African 

 Gerbille that little doubt can exist as to their specific identity 

 with it. 



10. Cricetomys gambianus, Waterh. 

 a, b. 2 yg. al. $ . 



11. Mus RATTUS, var. 



c. Ad. sk. Milanji Plain, 4000 ft. 25/10/91. 

 b-d. In al. 



One of the numerous brown tropical varieties of the common 

 Mus raltus. 



12. Mus DOLiCHURUs, Smuts. 



a, b. Ad. and imm. sk. Zomba. 8/8/91. 



These specimensrepresent, of course, Peters's M.arborarius,vihich, 

 as already mentioned ^, I cannot distinguish specifically from 

 M. dolicliurus. As this long-tailed Tree-Mouse seems to be rare 

 throughout its wide range, tliese examples are very welcome acces- 

 .sions to the Museum collection. 



13. Mus NATALENSIS, A. Sm. 



a. Ad. sk. Zomba. 19/1/92. 



(?) b. Zomba. 17/9/91. 



c-e. 3 in. al. 



This appears to be the Mus microdon of Peters. 



14. Mus MUSCULUS, L. 



a, b. 2 in al. 



The fur of these specimens is rather crisp and spiny, and it may 

 be that when the nmscidus group is worked out in detail the South 

 African form will require a distinct name. One of Sir Andrew 

 Smith's specimens in the Museum is also similarly spiny, and belongs 

 no doubt to the same race. All the essential characters, including 

 the skull and teeth, are quite as in normal M. mnsculus. 



15. Mus (Leggada) minutoides, A. Sm. 

 a-e. 10 in al. 



These specimens represent, of course, Peters's iliws minimus, 

 synonymous, as I believe, with Smith's previously described species. 



1 P. Z. S. 1891, p. 186. 



