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PACIFIC SCIENCE, Vol. XV, October 1961 
Clethrionomys rutilus 
J 5mm 
Clethrionomys Clethrionomys 
niigatae rufocanus 
Clethrionomys 
Clethrionomys imaizumii 
Eothenomys kageus Eothenomys smithi 
Fig. 1 . Enamel patterns of Japanese red-backed voles. 
