PLATE LXXX. — SKULL OF MEPHITIS HUDSONICA rS (NATURAL SIZE). 

 Cut from A. H. Howell's " Revision of the Skunl;s," plate VI. N. A. Fauna, No. 20, looi. Biological Survey. U. S. Dep. .'^gr. 



PL.ATE LXXXI. — SKULL OF MUSTELA AMERICANA (naTUR.AL SIZE). 

 Cut from \V. H. Osgood's " Yukon Region." p. 44. N. A. Fauna, No. 19, 1900, Biological Survey, U. S. Dep. Agr. 



