FEB., 1912. MAMMALS OF ILLINOIS AND WISCONSIN CORY. 339 



form and apparently show marked intergradation. When the time 

 comes that a sufficiently large series from various localities can be 

 gathered together for comparison, it may be found that all of our 

 large Skunks belonging to this genus are merely geographical races of 

 one or possibly two species, four of which intergrade within our limits. 

 For the laity it is perhaps as well to consider all the Skunks belonging 

 to the genus Mephitis, which are found within our limits, to be either 

 hudsonica or avia, but many specimens are* not typical of either and 

 possess characters more or less approaching mephitis or putida, as 

 shown by the following brief descriptions of a series of Skunks in the 

 Field Museum collection from Green Bay, Wisconsin. The measure- 

 ments are in millimeters. 



No. 11708, 9 Palate with distinct median spine, but zygomata widely expanded; 

 white stripes extending on sides of tail about y$ its length; end of tail blunt and 

 entirely black. 



Total length, 625; tail vertebrae, 195; hind foot, 63.5. 



No. 11706, 9 Palate with distinct median spine and skull similar to preceding; 

 tail mostly black, but ending with a long white pencil. 

 Total length, 660; tail vertebras, 220; hind foot, 68. 



No. 11704, cf Palate with indication of median spine; skull narrower than 

 hudsonica and zygomata approaching mephitis; white stripes extending on sides 

 of tail to about > its length; end of tail blunt and entirely black. 



Total length, 615; tail vertebrae, 185; hind foot, 64.5. 



No. 11703, cf Palate evenly rounded, without spine; white stripes extending on 

 tail y$ its length; end of tail black. 



Total length, 560; tail vertebrae, 174; hind foot, 56.5. 



No. 11702, o" Palate without median spine; skull narrower and zygomata 

 approaching mephitis more than avia; white stripes extending on tail; whole end 

 of tail broadly white. 



Total length, 600; tail vertebrae, 215; hind foot, 61. 



No. 11701, c? Skull badly broken; zygomata badly broken and absent; white 

 stripes extending on sides of tail; end of tail blunt and entirely black. 



Total length, 655; tail vertebrae, 230; hind foot, 74. 



No. 11707, 9 Skull badly broken; palate without median spine; white stripes 

 extending on sides of tail about % its length; tail mixed with long white hairs; 

 end of tail black. 



Total length, 675; tail vertebrae, 220; hind foot, 67.5. 



No. 11720, 9 Skull large but badly broken, palate without median spine; white 

 stripes extending but slightly on base of tail; end of tail black, with a few long 

 white hairs extending from the tip. 



Total length, 685; tail vertebrae, 220; hind foot, 70. 



No. 11721, 9 Palate evenly rounded, without median spine; skull approaching 

 mephitis; white stripes short, not reaching the rump; rump entirely black; tail 

 black, with the whole end white for about 4 inches. 



Total length, 635; tail vertebrae, 215; hind foot, 69. 



No. 18395, c? Galena, Illinois, Skull resembling avia, but white stripes of body 

 extending on sides of tail nearly to the end; end of tail black; a small white spot 

 on the lower part of the throat. 



Total length, 623; tail vertebrae, 258; hind foot, 75. 



