36 Mr. M. A. C. Hinton on new 



Remarks. — In view of what Dr. Forsyth Major has stated 

 on a previous occasion *, it is exceedingly satisfactory to find 

 a Pleistocene forerunner of M. orcadensis upon the British 

 mainland. In turn it may be stated that the existence of 

 another member of the same group in the Channel Islands, 

 M. sarnius f, seems to indicate that we received M. corneri 

 from France. At Ightham we find in addition skulls of a 

 smaller member of the arvalis group possessing close affinity 

 with the M. arvalis of Belgium, and this I think came to 

 Britain by another route — across the bed of the North Sea — 

 during the last great elevation of North-western Europe in 

 very late Pleistocene times. This subject is more fully 

 dealt with in a paper shortly to be published in the ' Pro- 

 ceedings of the Geologists' Association.' 



Microtus anglicus, sp. n., foss. 



Type. — A nearly perfect adult skull in the collection of 

 Dr. Frank Corner from the Ightham Fissures (Late Pleisto- 

 cene). 



Characters. — Skull essentially as in the Asiatic " Steno- 

 cranius " group of Kastchenko, long and narrow ; rostrum 

 long, broader than interorbital region ; interorbital region 

 greatly constricted, the temporal ridges in adults meeting 

 early to form a long well-defined saggital crest ; zygomatic 

 arches heavy and, for " Stenocranius" flaring ; postorbital 

 (squamosal) processes prominent ; brain-case shorter than in 

 extreme " Stenocranius ; " interparietal large, rather loig 

 antero-posteriorly ; diasteme long ; incisors protruding be- 

 yond nasal tips ; palate narrow, boldly sculptured with d«ep 

 postero-lateral pits and very narrow median septum. 



Dentition : maxillary molars having the general pattern of 

 M. arvalis group ; mandibular molars, the anterior one with 

 five closed triangles as usual, the fourth outer angle greatly 

 reduced, so that the external border of anterior loop ii 

 perfectly straight typically ; antero-external triangle of last 

 lower molar greatly reduced; enamel sheet in all molars well 

 differentiated, the thin portions, forming posterior walls of 

 prisms of lower and anterior walls of pi isms in upper molars, 

 frequently obsolete. 



* Forsyth Major, Ann. & Mag. Nat. Hist. ser. 7, vol. xv. 1905, p 324 

 f Miller, Ann. & Mag. Nat. Hist. ser. 8, vol. iii. 1909, p. 420. The 

 type of M. sarnius is very old and its skull very narrow. Mr. Millar was 

 led accordingly to regard the species as a member of the 31. qgrestis 

 group. Further material has turned up, and Mr. Miller now fully agrees 

 with the view expressed above as to the affinity of this form. "j ' 



