718 



Diagnosis. — Similar to Microtus nivalis nivalis, but anterior 

 loop of first lower molar broadly orescentic in outline, the postero- 

 external salient angle broad and rounded, occasionally obsolete. 



Enamel pattern of Microtus nivalis nivalis (a) and 

 M. nivalis aquitanius (6). X 5. 



Measurements. — Type (young-adult male) : head and body, 111; 

 tail, 59 ; hind foot, 21 ; ear, 16. Two adult males from the type 

 locality: head and body, 124 and 124; tail, 61 and 64; hind 

 foot, 20 • 4 and 2 1 ; ear, 1 7 • 8 and 1 9 • 4. Adult male from Pic-du- 

 Midi, Hautes-Pyrenees : head and body, 129 ; tail, 71 ; hind 

 foot, 21 ; ear, 17. For cranial measurements see Table, p. 721. 



Specimens examined. — Fourteen, from the following localities on the 

 French side of the Pyrenees : Porte, Pyrenees-Orientales, 2 ; l'Hospitalet, 

 Ariege, 5 ; Bareges, Hautes-Pyrenees, 1 ; Pic-du-Midi, Hautes-Pyrenees, 6. 



2 9. Porte, Pyrenees ■ 



France. 



3 6. L'Hospitalet, Ariege. 



3 6,39. Pic-du-Midi, Hautes-Pyrenees. 

 (A. Robert.) 



Orientales, G. S. Miller (c). 8. 8. 4. 240-241. 



G. S. Miller (c). 8. 8. 4. 237-239. 

 (8. 8. 4. 238. Type of subspecies.) 

 0. Thomas (p). 8. 9. 1. 64-69. 



MICROTUS LEBRUNII Crespon. 

 (Synonymy under subspecies.) 



Geographical distribution. — Central and south-eastern Prance 

 from Puy-de-D6me to the Departments of Gard, Var, and Basses- 

 Alpes. 



Diagnosis. — Like Microtus nivalis, but smaller (hind foot in 

 adults less than 20 mm. ; condylobasal length of skull less than 

 28 mm.), and paler, the tail always pure white throughout, and 

 the back a light grey without conspicuous brownish suffusion. , 



Skull. — Except for its smaller size, the skull does not differ 

 tangibly from that of M. nivalis. 



Teeth. — As compared with those of M. nivalis of the same 

 age, the teeth differ in their slightly smaller size, but I can find 



