94 JOURNAL OF MAMMALOGY 



and vancouverensis, and in the picatus series there is individual vari 

 tion tending to bridge the gap in either direction. The indentation 

 the orbital arch, given by Osgood as a feature distinguishing petuh 

 from vancouverensis, is not a character to be absolutely relied upc 

 This httle notch is sharply indicated in the petulans series, as I belie 

 it is in the red squirrels of the interior of the northwest generally, 

 the Vancouver Island skulls at hand there are none in which it is at i 

 deeply cut. In some it is entirely absent, but usually there is a sv 

 gestion of a notch at that point. The southern Alaskan series contai 

 none in which the notch is as nearly eliminated as in most of the Va 

 couver Island skulls, and as a rule it is as apparent as in the petula 

 series. It is not a character the presence or absence of which c 

 be indicated in each of the skulls; it appears in all degrees from o 

 extreme to the other. 



Berkeley, California. 



