PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM 



issued 8^l^v>LCl?^ h (fte 



SMITHSONIAN INSTITUTION 



U. S. NATIONAL MUSEUM 



Vol 104 Washington : 1955 No. 3346 



MODIFICATIONS OF PATTERN IN THE AORTIC ARCH SYS- 

 TEM OF BIRDS AND THEIR PHYLOGENETIC SIGNIFICANCE 



By Fred H. Glenny ^ 



Introduction 



My interest in the aortic arch system in birds was stimulated by 

 the discovery of a functional left radix aortae in the belted king- 

 fisher during a routine dissection of that bird in 1938. Subsequent 

 studies on several other species of birds produced interesting ana- 

 tomical information, and, with continued studies, a semblance of 

 order in occurrence of carotid patterns became more and more 

 evident. 



After a reasonably large series of families and orders of birds had 

 been examined, it appeared that further studies might produce in- 

 formation which could be of value in avian taxonomy. As a result, 

 a series of systematic studies of the main arteries of the neck and 

 thorax of birds was initiated and carried out over a period of about 12 

 years. 



During the past 2 or 3 years important implications with respect 

 to the evolution of the aortic arch system in the bhds became more 

 apparent, and the present treatise deals primarily with this aspect of 

 my accumulated studies. 



The classification of birds used in this study follows the arrange- 

 ment of Wetmore and Peters, with only a minor revision in the 

 listiag of the parrots in the subfamily Psittacinae. In my opinion, 

 the Wetmore and Peters classification of the birds of the world is more 

 in accord with the natural relationships than are the schema employed 

 by many of the European taxonomists. 



Insofar as possible the names of birds as used bj^ earlier and even 

 contemporary writers have been checked as to sjiionymy with 

 Peters' (1931-51) checklist. Since Peters' checklist is not complete 



'■ The Youngstown University, Youngitown, 0hio< 



332543—55 1 525 



