202 Mr. G. R. Waterhouse on the Rodentia. 



front between the molars (which are permanently *~) 9 and 

 is rather deeply emarginated behind*. 



Among the Muridae is a tolerably well-marked section, at 

 present limited in number of species, but to which I antici- 

 pate many novelties will be added, especially from those por- 

 tions of the old world which lie between 30° and 40° north lati- 

 tude, of which the genus Spalax may be regarded as the type, 

 and which might conveniently be raised to the rank of a sub- 

 family under the name Spalacina or Aspalomyina f . Agree- 

 ing essentially with the Muridce, the Aspalomyince are distin- 

 guishable by the comparative great breadth of the skull, the 

 absence or almost total absence of the vertical slit, through 

 w T hich in the typical Muridce the infra-orbital nerve passes, 

 and which is defended by a nearly vertical thin bony plate ; 

 and, moreover, by the equal size of the molar teeth. In this 

 subfamily should be arranged Spalax, or Aspalomys, Hetero- 

 cephalus (Ruppell) and Rhizomys. 



The above families and subfamilies will therefore, according 

 to my views, be thus arranged : — 



Family 1. SciuRiDiE ; containing the genera Sciurus, Pteromys, Sciuropte- 

 rus, Xerus, Tamias, Spermophilus, and Arctomys. 



Aberrant forms. 

 Wanting post-orbital process to the frontals. 

 a, with large ant-orbital opening, and the palate contracted between the 

 anterior molars. 



* with rooted molars 4 -^j Anomalurus. 



* From the same collection three new species of squirrels were also de- 

 scribed by me. One, to which I gave the name Sciurus Stangeri ; a species 

 larger than the common squirrel, with coarse fur, freckled with black and 

 yellow on the upper parts of the body ; the abdomen very sparingly clothed, 

 and the tail very large and bushy — also presents an interesting modifica- 

 tion in the structure of the skull; this is unusually long, and has the ant-orbital 

 outlet remarkably short, opening directly through the bony plate which 

 forms the anterior root of the zygomatic arch, and not placed far forwards, 

 and in the form of a canal, as in other squirrels which I have examined. 

 The other two new squirrels, which were named Sc. rufo-brachium and Sc. 

 leucogenys, are of less interest : the former resembles the Sc. annulatus of 

 authors, but is rather larger, of a richer colour, and has the posterior part 

 of the fore- and hind-legs fringed with rusty-red hairs. The Sc. leucogenys 

 is of a rich brown colour above, (a tint produced by the admixture of black 

 and rich yellow, the hairs being freckled with the latter colour,) white be- 

 neath ; has the tail chiefly of a black colour, but the hairs tipped with white, 

 and red at the base ; the mesial portion of the tail beneath is, moreover, 

 bright rusty-red ; the sides of the face, as the name implies, are white. It 

 is about equal to the common squirrel in size. 



f It appears from some observations by M. Gervais (' Voyage de la Bo- 

 nite') that the name Aspalomys of Laxmann has priority of date over that 

 of Spalax, given by Guldenstedt, in which case I should take the name of 

 the subfamily from the older name as well as that of the genus. 



