Vol. XX -| Allen, The A. O. U. Check-Lht. -l 



1903 J o 



The changes in nomenclature have been due to two causes : (i) 

 the discovery of some older available name than the one originally 

 adopted; (2) that the name originally adopted was preoccupied 

 and therefore untenable. The number of changes in generic and 

 subgeneric names, including three corrections of orthography, 

 number less than 30 out of a total of 423, — 340 generic names 

 and %Ty subgeneric names, — or about 7.3 percent. 



The number of changes in specific and subspecific names is 63, 

 or less than six-tenths of one percent. 



But these changes, while relatively so few, necessitate a large 

 number of modifications in the designations of species and sub- 

 species ; the change of a generic name, or the raising of a sub- 

 genus to a genus, aft'ects all the species and subspecies of the 

 genus thus involved. Also the change of a single specific name 

 may entail a modification in the names of quite a number of sub- 

 species. 



The changes in generic names affect the names of 90 species 

 and 25 subspecies, or a total of 115 names. These changes are 

 additional to the 63 changes in specific and subspecific names. 

 In other words about one in every ten of the specific and sub- 

 specific designations in the Check-List have been modified to 

 some extent. 



As already said, the first edition of the Check-List was published 

 in 1886, and a second edition in 1895, since which date there have 

 been issued four supplements. The history of the Check-List thus 

 falls into two periods, the first of nine years, from 1886 to 1895, 

 and the second of seven years, from 1895 to 1902. It may be of 

 interest to compare statistically these two periods. 



The first Check-List contained 768 species and 183 subspecies, 

 or a total of 951 named forms; the second contained 802 species 

 and 268 subspecies, or a total of 1070; the net gain in nine years 

 having been 34 species and 85 subspecies. 



In July, 1902, the Check-List and supplements contained 822 

 species and 364 subspecies, or a total of 1186 forms, the net gain 

 in seven years having been 20 species and 96 subspecies. There 

 was thus practically an equal increase in these two unequal periods, 

 with a rather greater ratio of increase in the subspecies as com- 

 pared with the species in the second period. 



