MIMOMYS 351 



mens from the Italian Pliocene were rooted and not developed 

 from persistent pulps as in the Water Vole. Ten years later, 

 and quite independently, Newton made a similar discovery with 

 respect to the British species, and he accordingly referred all 

 the remains before him to a new species, Arvicola intermedius, 

 which he placed in the subgenus Evotomys. In 1894 Nehring, 

 studying somewhat similar material from the Pliocene of Hungary, 

 realized that voles of this kind were quite different from Evotomys, 

 and so he referred them to Phenacomya, a remarkable N. American 

 genus described a little earlier by Merriam. Miller pointed out 

 shortly afterwards that the reference to Phenacomys was erroneous. 

 Thereupon Nehring described his genus Dolomys, basing it upon 

 one of the Hungarian species before him and referring to it the 

 remains previously described from the Pliocene of Britain and 

 Italy. In 1902 Forsyth Major found that the British and 

 Italian forms were not congeneric with the Hungarian Dolomys 

 milleri, and he established his genus Mimomys for their recep- 

 tion. In the same year White and the present writer found 

 that the genus had lingered in Britain until the early Pleistocene 

 (High Terrace of the Thames), and we referred the remains from 

 that horizon to " Microtus intermedins " Newton, a well-known 

 Forest Bed species. In 1910 I accorded Mimomys full generic 

 rank, and briefly diagnosed four new species from British deposits. 

 Lastly in 1914 Mehely published a complete and beautifully 

 illustrated account of the Hungarian fossils. He showed that 

 the deposits of that country contained in addition to Dolomys 

 milleri the remains of several other species with rooted molars. 

 Two of these he regarded as congeneric with Mimomys; but 

 on others he based three new genera, viz., Pliomys, Apistomys, 

 and Microtomys, of which the last-named, for reasons given below, 

 is regarded by me as a synonym of Mimomys. 



Having regard to its bearing upon the systematics of the 

 present genus it is, perhaps, most convenient to intercalate the 

 following note upon Mehely's work at this place, although the 

 matters dealt with are partly those which I have endeavoured 

 to expound in the introduction to this Monograph. 



Mehely divides the Microtinse into three super-genera, viz., 

 Lemmi, Microti, and Fibrince ; he includes in the last named all 

 living and extinct genera with rooted molars. To my mind 

 this is rather an ill-conceived classification, because the 

 " FihrincB " are merely relatively primitive types which may 

 belong either to Microti or Lemmi. It so happens that all 

 known " Fibrince " link themselves with Microti and not 

 with Lemmi; but that Lemmi also have had ancestors provided 

 with rooted molars is a very safe inference to be drawn from 

 present knowledge. In any case the "' Fibrince " cannot be 

 regarded as forming a division equal in rank to those of the 

 Lemmi and the Microti. 



Mehelv further subdivides the " Fibrince " into two sections : — 



