I/O SHUFELDT. 



EXPLANATION OF PLATE XVII. 



Fig. 13. Skull of Syrnium aluco ; left lateral aspect, with mandible attached ; 

 natural size. 



Fig. 14. Skull of Syrnium aluco; anterior aspect, ^ith mandible attached; 

 natural size. 



Fig. 1 5. Skull of Syrnium uralense ; anterior aspect, with mandible attached ; 

 natural size. 



Fig. 1 6. S kull of Syrnium uralense ; left lateral aspect, with mandible attached ; 

 natural size. 



