12 Miller — A New Vole from Eastern Siberia. 



seven skulls of M. kamiscluUicus), tiiid the palate difters notably from that 

 of any of the specimens of M. kamtschaticus in 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. kanilscJtalicas, and the articular and 

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

 tsliorum shows an approach to M. nrvalis of Europe, and an even closer 

 resemblance to 3T. kadiacensis. 



Teeth as in M. kamtschaticns. 



Measurements. — Total length, 111); tail vertebrte ; 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. 



