12 Miller A New Vole from Eastern Siberia. 



seven skulls of M. kamtochaticus), and the palate differs notably from that 

 of any of the specimens of Af. kamtochaticus La the small size and insignifi 

 cant number of foramina immediately in front of the lateral bridges. As 

 a result the bridges are not distinguishable. The mandible is conspicu 

 ously more slender than that of M. kamtscliaticus, and the articular and 

 angular processes are very noticeably weaker. In this respect Af. tshuk- 

 Ishorum shows an approach to M. arvalijt of Europe, and an even closer 

 resemblance to M. kadiacensis. 



Teeth as in AL kamtschatlcus. 



Measurements. Total length, 113; tail vertebrae; 29; pencil, 8 ; hind 

 foot (with claws), 19; ear from meatus, 10; ear from crown, 8. Skull : 

 greatest length, 23.8; basal length, 23; basilar length, 21.6; zygomatic 

 breadth, 13; interorbital constriction, 4 ; mastoid breadth, 12; palatal 

 length, 12.4 ; diastema, 7.8 ; nasals, 5.8 ; incisive foramen, 4 ; mandible, 

 14.8; maxillary tooth row (alveoli), 0.4 ; mandibular tooth row, 6. 



