"iQiO J Recent Literature. 471 



cases where material for their investigation was in the first instance scanty 

 and later became more adequate. 



It is of interest to note that most of the species added to the Check- 

 List since the publication of the first edition have been either waifs and 

 strays from extralimital regions, or insular forms from the Aleutian Is- 

 lands, or species recently described from the peninsula of Lower California 

 and its contiguous islands. By far the greatest part belong to the category 

 of accidental species pertaining properly to the fauna of Europe and Asia 

 but occurring casually in Greenland and Alaska, or West Indian and Mexi- 

 can species of casual occurrence within the Check-List limits, and a few 

 that have been found to range slightly bej^ond the northern border of 

 Mexico. Nearly one-half of these additions are water birds, as petrels 

 (Tubinares), ducks and geese (Lamellirostres), and shore birds (Limi- 

 colae) ; several others are West Indian pigeons and swallows. 



The species of merely casual or accidental occurrence within the Check- 

 List limits (indicated by the enclosure of the number designating them in 

 brackets in the first and second editions, and as bracketed insertions in 

 the third edition) form, owing to their large number, a rather prominent 

 feature of the list, the total (including all the editions) being 119. Of 

 these 88 are still retained, the others proving to have been improperly 

 included. This is only six more than the number contained in the first 

 edition, but the constituency of the bracketed list has been much changed 

 by additions and eliminations. This feature, in fact, serves as an indica- 

 tion of progress in our knowledge of North American birds. Thus it has 

 been found proper to remove the brackets in the case of 17 species given 

 as bracketed species in the first and second editions, these species, though 

 rare, having proved to be of sufficiently frequent occurrence to be regarded 

 as proper elements of the Check -List fauna. At the same time 14 others 

 have been wholly eliminated as being without a satisfactory record of 

 occurrence within the limits of the Check-List, while 28 others have been 

 added on the basis of authentic records of capture. 



The Hypothetical List also shows changes of similar character, it num- 

 bering 26 species in the first edition, 27 in the second, and 20 in the third, 

 notwithstanding the addition of 5 species in this edition. Of the total of 

 34 species referred to it, 3 have been transferred to the main list and 11 

 eliminated as having not even a hypothetical claim to recognition as 

 species of the Check-List area. 



The List of Fossil Birds has nearly doubled since the first edition, has 

 been reclassified, and otherwise made more satisfactory and useful. From 

 46 species in the first edition the list increased to 64 in the second, and to 

 72 in the third, which comprise all of the known fossil birds of North 

 America to the close of the year 1909. 



It would be out of place for the present writer to dilate on the merits 

 of the 'New Check-List,' which will doubtless be welcomed as bringing 

 together in convenient order the numerous additions and nomenclatorial 

 changes previously scattered through eight Check-List Supplements. 



