new European Mammals. 459 



Dyromys robustus, sp. n. 



Type. — Adult female (in spirit). Collected at Rustchuk, 

 Bulgaria, by K. Andersen. 



Characters. — Like Dyromys nitedula, but skull broader and 

 more robust, with relatively shorter rostrum and much en- 

 larged audital bulla?. 



Measurements. — Head and body 95 mm.; tail 87; hind 

 foot 22 ; ear from meatus 15 ; condylo-basal length of skull 

 25 # 6 ; zygomatic breadth 16*8 ; mastoid breadth 13*6 ; man- 

 dible 15*2 ; maxillary tooth-row (alveoli) 3*8 ; mandibular 

 tooth-row 4*2 (teeth slightly worn). 



Specimen examined. — The type. 



Remarks. — In its peculiar broad robust skull, relatively 

 short rostrum, and enlarged audital bullae this animal differs 

 from all the hitherto known European races of D. nitedula 

 as well as from the Asiatic members of the genus. 



Microtus dentatus, sp. n. 



Type. — Adult female (skin and skull). Collected at Moli- 

 nicos, Sierra de Segura, Albacete, Spain, December 11, 1908. 



Characters. — Similar to Microtus cabrero3, Thomas, of 

 Central Spain, but larger, the skull about 30 mm. in condylo- 

 basal length ; teeth excessively heavy, larger than in any 

 other known European Microtus, the maxillary tooth-row 

 8 mm. in length ; m z with completely closed triangle on outer 

 side ; colour paler and less buffy. (Ground-colour of back and 

 sides less yellow than the cream-buff of Kidgway, the general 

 effect a peculiar buffy grey, noticeably different from the olive 

 or bistre of M. Cabreras; underpaits light grey, scarcely 

 tinged with buff.) 



Measurements. — Type. Head and body 125 mm.; tail 40; 

 hind foot (dry) 22 ; upper length of skull 29'4 (in type of 

 cabrerce 26*6) ; condylo-basal length 30+ (in type of cabrerce 

 27*0) ; mandible 19 - ; maxillary tooth-row (alveoli) 8'0 ; 

 mandibular tooth-row 7'6. 



Specimen examined. — The type. 



Remarks. — I owe to the kindness of Mr. A. Cabrera the 

 opportunity of examining the type and only known specimen 

 of this species. The animal is evidently related to Microtus 

 cabrerce, but its unusually large molars immediately distin- 

 guish it among the European members of the genus. The 

 presence of a completely closed triangle in the posterior lower 

 molar is equally unusual. 



31* 



