320 University of California Publications in Zoology. [Vol. 7 



forward and recorded. The biological explorations made in the 

 Pine Forest Mountain region were prosecuted with this principle 

 in mind; and in the present paper detailed facts of possible 

 f aunal and distributional significance have been emphasized. 

 , At the present time it is coming to be realized that there are 

 Other characters distinguishing species than those brought for- 

 ward through morphological researches, as, for example, those 

 belonging to the domains of physiology and psychology. These 

 characters, being less accessible and sometimes less tangible, offer 

 more obstacles to precise definition than those others dealing 

 with structure. Nevertheless, traits, habits, manners of perform- 

 ing particular acts, preferences of one kind and another, seem 

 in most cases to be as definite and as constant characteristics of 

 species as the shape and size of bill and feet, or coloration of 

 fur and configuration of skull. An attempt has in this paper 

 been made to place the emphasis upon such non-morphological 

 characters, here mainly psychological. That the facts as recorded 

 are in some cases fragmentary and unrelated to others indicates 

 strongly the general desirability of putting on record such data 

 as are available, to the end that later investigators in this field 

 may at least benefit by that little which is at present known. 



This paper represents the completion of the report on the 

 vertebrates of the Pine Forest Mountain region, the first major 

 installment of which appeared as the ' ' Mammals of the Alexander 

 Nevada Expedition of 1909" (Taylor, 1911). 



While Mr. Richardson and the writer were carrying on field 

 work in the Pine Forest Mountain region. Miss Alexander and 

 Miss Kellogg were members of a palaeontological expedition 

 working in the same general neighborhood (see Taylor, 1911, 

 p. 205). They incidentally collected specimens of vertebrates 

 and made field notes. The results of their work as well as of our 

 own have been incorporated into the present paper. 



The writer must acknowledge indebtedness to the following 

 persons : to Professor Charles A. Kofoid, of the Department of 

 Zoology of the University of California, for generous criticism; 

 to Mr. Joseph Grinnell, Director of the Museum of Vertebrate 

 Zoology of the University of California, for general direction and 

 advice in connection with the paper; to Professor Harvey M. 



