526 PROCEEDINGS OF THE NATIONAL MUSEUM vur. 104 



for the Passeriformes, only the authority for the species listed can be 

 given. 



The British Museum catalog of birds and Sharpe's hand-list have 

 been freely consulted in an effort to obtain information essential to 

 the establishment of the names of species and subspecies synonymous 

 with those in the Peters checklist. 



Unless otherwise noted, only smgle specimens were studied; in 

 instances where more were studied the number is noted after the 

 species name. 



I wish to express sincere gratitude to the following individuals and 

 institutions for their generous assistance in making available ma- 

 terials used in the study, and for their many helpful suggestions and 

 criticisms in the preparation of this paper: American Museum of 

 Natural History; Chicago Natural History Museum; Cleveland 

 Museum of Natural History; Fan Memorial Institute of Biology; 

 Meems Brothers and Ward, Inc.; Royal Ontario Museum of Zoology; 

 Sudan Government Museum, Natural History; United States Na- 

 tional Museum; and Ward's Natural Science Establishment, Inc.; 

 Dr. Jolm. W. Aldrich, Dr. Dean Amadon, Dr. Doris Cochi-an, Mr. J. W. 

 Cowland, Dr. E. Home Craigie, Dr. David E. Davis, Mr. Dwight D. 

 Davis, Dr. Charles A. Dambach, Mr. R. N. Deaton, Dr. E. H. 

 Dustman, Dr. Herbert Friedmami, Dr. Ira N. Gabrielson, Dr. D. L. 

 Gamble, Mrs. M. E. Glenny, Mr. W. Earl Godfrey, Dr. Walter C. 

 Kraatz, Mr. W. J. Leach, Mr. Ben H. Morgan, Mrs. C. P. Mountz, 

 Dr. Harry C. Oberholser, Dr. John W. Price, Dr. Loren S. Putnam, 

 Dr. D. P. Quiring, Mr. Tsen-Hwang Shaw, and Dr. Alexander 

 Wetmore. 



Review of the literature 



From shortly after the turn of the 19th century until its end, 

 Em-opean anatomists and ornithologists evinced a considerable in- 

 terest in the arterial system of birds. Among the earliest writers on 

 this subject were Bauer, Meckel, Nitzsch, and Hahn, followed by 

 Owen and Barkow. With the rapid expansion of interest in com- 

 parative morphology during the middle of the 19th century, other 

 workers soon became engaged in numerous and very revealing in- 

 vestigations to which they tried to give some semblance of order and 

 meaning. Prominent among this group of workers were Boas, 

 Rathlce, Sabatier, and Garrod. 



During the middle of the 19th century, the theory of ontogenetic 

 recapitulation was developed and became of considerable importance 

 in the fields of comparative and human anatomy and organic evolution. 

 It was during this time that the study of anatomy received its greatest 

 impetus and achieved the peak of respectability in science. 



Garrod, of all the workers of his time, was least successful in in- 

 terpreting his findings, with the result that the significance of his 



