HYPOTHETICAL LIST. 



'THIS list which has appeared in each of the three preceding editions of the 

 Check-List has been supposed to consist "of species which have been 

 recorded as North American, but whose status as North American birds is 

 doubtful, either from lack of positive evidence of their occurrence within the 

 prescribed limits of the present Check-List, or from absence of satisfactory 

 proof of their validity as species." 



It might be better to divide them into three categories instead of two, viz: 

 I. Valid species the record of whose occurrence in North America is open to 

 question. II. Forms described as distinct species or subspecies but which 

 are now regarded as hybrids, color phases or individual variations. III. 

 Alleged species based on plates of Audubon and Wilson which have never 

 been satisfactorily identified. 



Occasionally subspecies upon the validity of which the Committee has not 

 been able to decide have been referred to this list instead of being held in 

 abeyance as has usually been the custom. With additional information avail- 

 able these have been properly disposed of while other forms originally in the 

 Hypothetical List have been restored to the Check-List or have been dropped 

 entirely. As it seems important to keep a record of such action all species 

 that have at any time appeared in the Hypothetical List are included in the 

 present edition, those which have been removed in previous editions being 

 placed in brackets with a statement as to their disposition, while some of this 

 information is also contained in foot notes to the preceding pages. Species 

 which have been restored to the regular List are also marked with a star. 



The separate series of numbers for the Hypothetical List has been abandoned 

 and only those species are numbered which are now or have been included in 

 the regular List.^ 



^ Of the species listed in the Hypothetical List of the third edition four have 

 been transferred to the regular List viz: Anas rubripes trisiis, Pisobia ruficoUis, 

 Numenius arquatus (as N. arquatus arquatus) and Totanus totanus (as T. 

 totanus robustus) while eleven species have been transferred from the regular 

 List of the third edition to the Hypothetical List viz: Phoebetria palpebrata 

 (as P. p. auduboni), PrioceUa glacialoides (as P. antardica), Macronedes 

 giganteus, Ixobrychus neoxenus, Jabiru mycteria, Mergellus albellus, Glottis nebu- 

 laria, Larus nelsoni, Larus kumlieni, Starnoenas cyanocephala, and Spinus 

 notatus. Three species: Thalassogeron dirysostonms (see explanation p. 366), 

 Thyellodroma pacifica, and Mesophoyx intermedia which did not appeal' in any 

 part of the third edition have been added. 



365 



