MURIDsE 



465 



Fossil remains of Neotoma from cavern-deposits in Pennsylvania 

 are not improbably referable to the existing Florida Rat (N. 

 floridana). Paciculus, from the Miocene of the United States, is 

 regarded as an allied extinct genus with enamel-folds to the molars. 



Hypogeomys. 1 This and the following genera are confined 

 to Madagascar, where they are the sole representatives of the 

 Rodentia. Hypogeomys is a very peculiar form of large size, with 

 long ears, feet, and tail. There is only one species, H. antimena, a 

 fawn-coloured Rat about 9 inches long. 



Nesomys. 2 Contains two species of long-haired Rats, more or 

 less rufous in colour, about the size of the Brown Rat. 



JBrachytarsomys. 3 Represented only by B. albicauda, a pretty 

 velvety-haired fawn-coloured Rat, with short feet and a long tail. 



Hallomys* The only species (H. audeberti} is very like a 

 Nesomys, but has much longer hind feet. 



Eliurus. 5 Represented by one small Dormouse -like species, 

 characterised by its nearly naked and short ears, and long tail, of 

 which the proximal third is scaly, and the remainder covered 

 with long hair. The pollex is rudimental, but the hallux well 

 developed. 



Subfamily Arvieolinse. Molars usually imperfectly rooted or 

 rootless, and composed of two longitudinal rows of triangular 

 prisms placed alternately 

 (Fig. 207). Tail moderate 

 or short. Common to the 

 Palaearctic and Nearctic 

 regions. 



The Voles, as the members 

 of this group are commonly 

 termed, are so closely con- 

 nected with the Cricetines 

 that they may be regarded 

 merely as a branch of that 

 subfamily which has attained 

 a peculiarly specialised type 

 of molar dentition. The 

 Voles are externally dis- 

 tinguished, as a rule, from true Rats and Mice by their more 

 clumsy and heavy build and less graceful movements ; by the small 

 size of their eyes, the bluntness of the muzzle, the small ears, and 

 the shorter limbs and tail. 



1 Grandidier, Rev. and Mag. Zool. 1869, p. 388. 

 2 Peters, Sitzber. Ges. Nat. Freunde, 1870, p. 54 (1871). 



3 Giinther, Proc. Zool. Soc. 1875, p. 79. 



4 Jentink, Notes Leyd. Mus. vol. i. p. 107, note 27 (1879). 



5 Milne-Edwards, Ann. Sci. Nat. ser. 6, vol. xx. art. 1, bis, p. 1 (1886). 



30 



FIG. 207. Upper (A) and lower (B) molars of the 

 Water- Vole (Arvicola amphibius). 



