PREFACE xvii 



more widely separated than the horse from the ass, are fer- 

 tile inter se. 



It must be understood, therefore, that "species" is as 

 purely a term of convenience as *' genus." It designates all 

 the animals of a certain type which it is convenient to group 

 together under one name, both to indicate their more or 

 less close relationship to one another, and their greater or 

 smaller dissimilarity from other forms. As the term is one 

 of convenience and should indicate relationship, it is well 

 not to over-refine it in using it on ordinary occasions — that 

 is, not to become a species-splitter — and, as far as possible, 

 to use it so that there may be some rough approximation 

 between what is meant by species in one case and in an- 

 other. In technical scientific treatises the use merely of 

 generic and specific terms may not be sufficient to indicate 

 the finer differences; in such event it is unwise to make a 

 fetich of binomial Latin terminology — in itself also a pure 

 convenience — and it is well to use freely a trinomial, or 

 quadrinomial or pentanomial terminology. But in ordi- 

 nary writing, not only for scientific laymen, but for intelli- 

 gent laymen of all kinds, and also for scientists not so much 

 absorbed in details as to lose sight of the importance of the 

 whole, it is well to use the word *' species" in as large, as 

 ample, a sense as possible. Any needed further definition 

 can be made by the use of such words as subspecies, vari- 

 eties, geographical races, and the like. 



Mr. George Shiras, out of his own experience, recently 

 supplied a case in point. Mr. Shiras, although he would 

 disclaim the title, is a faunal naturalist whose photographs 

 of and notes on the big game and various other mammals 

 and various birds of the North American wildernesses are 



