MAMMALS OF MINNESOTA. 15 



word mammal is heard is derived, not from such a rigid analysis 

 as is necessary to formulate a scientific definition, but from men- 

 tal images of various mammals and these concrete images com- 

 monly are more or less clearly or vaguely implied even in the ab- 

 stract notion mammal. Such abstractions are only in so far valu- 

 able as they serve as keys to admit us with promptitude to that 

 chamber of our memory where are stored the various concrete 

 images which experience has gathered and which may be com- 

 pared with each other and thus produce an indefinite series of 

 abstract notions, varying in extension without altering the 

 fundamental conceptions of concrete things in the least. A 

 classification is in fact nothing but just such a series of gen- 

 eral notions and is, therefore, capable of being extended to any 

 number of terms, not greater thani the number of the individu- 

 als classified which are not positively identical. The person, 

 then, who desires to become conversant with zoology, or any 

 other branch of natural history, must strive to gather as great a 

 number of clear individual images of as great a variety of ob- 

 jects as his mental classification will enable him to retain 

 without confusion. 



It will be our aim then to present a verbal and pictorial image 

 of all the mammals in our state, hoping to thus impart more 

 real information than would be derived from lengthy and per- 

 chance learned discussions of the principles of classification or 

 theories of derivation or development. 



The following statistics will briefly summarize the mammal- 

 ian population of our state: 



1. Number of species known to exist 63 



2. Species rapidly approaching extinction , 8 



3. Species increasing in abundance 6 



4. Species of economic value 21 



5. Species which may be regarded as injurious 24 



6. Species having northern or sub-arctic affinity 6 



7. Species having a western affinity , 8 



8. Species belonging to the eastern province 25 



9. Species of general distribution in North America 24 



Of course in a relative matter of this sort opinion would vary 

 as to the inclusiveness of one or other of the categories; the 

 above table will merely indicate the approximate state of the 

 fauna. 



Among mammals either actually extinct in our limits or like- 

 ly to be so may be mentioned the buffalo, prong-horn, beaver, 

 wolverine, elk, caribou, gray gopher, and panther. The in- 

 troduced species of mice and rats are on the constant increase, 



