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HIE AMKRICAN X ATI' BALI ST [Vol. XLIII 



of assurance to the form they most closely resemble, but many specimens 

 fall so near the imaginary line between two or more subspecies that it 

 is practically impossible to classify them other than as intergrades. A 

 particularly troublesome class is one which approximates the color of 

 one form and the cranial characters of another, thus reducing the ques- 

 tion to one of relative importance of characters. 



In view of the foregoing it is evident that taxonomic difficul- 

 ties can easily arise, not only in this but in many other large 

 groups of nonspecific forms, through the unconscious, and hence 

 unavoidable, bestowal of names upon intermediate and unrepre- 

 sentative variants— upon connecting links between types that 

 reach their full development at some more or less distant point 

 from the locality which happened to be represented by the early 

 describer's limited material. While his act may have been justi- 

 fiable at the time from the circumstances of the case— absolute 

 ignorance, due to lack of material then nonexistent in collections, 

 of the range and variants of the group as a whole— it has re- 

 sulted in difficulties of synonymy and procedure that must for- 

 ever involve the subject, and introduce the element of personal 

 equation into their settlement. As said by Osgood, 



The reviser is often confronted with three names representing steps 

 in development, ... one of the designated forms being intermediate 

 between the other two. If, as often occurs, the recognition of only 

 two forms seems necessary, and the intermediate has been named before 

 either of the extremes, its name, having priority, must stand, and it 

 bcomes necessary to decide which of the names representing the 

 extremes shall lie considered a synonym. ... A reviser in dealing with 

 such names is compelled first to determine the number of recognizable 

 forms without regard to names. 



The type specimens are then referred, according to their re 

 semblance, to the recognizable forms, and the names of the forms 

 determined by the rule of priority. 



Another difficulty is the temperamental, the viewpoints of dif- 

 ferent authors as to what degree of differentiation entitles forms 

 to recognition. In the main Mr. Osgood has taken what appeals 

 to the present writer as a judicial course, and has threaded his 

 way with good judgment through the maze of difficulties insep- 

 arable from his subject. At all events he has methodized and 

 correlated our present knowledge of the group, and clearly pre- 

 sented the relationships of the scores of minor forms that com- 

 pose it. For the present at least it may be accepted and honored 



