THE EMBRYOLOGY OF THE BIRD'S LUNG' 



BASED ON OBSERVATIONS OF THE DOMESTIC FOWL 



PART V- 



WILLIAM A. LOCY AND OLOF LAR8ELL 



FORTY-SIX FIGURES 



FOREWORD 



The substance of this paper is the result of a combination of 

 observations on the part of the senior author extending over 

 several years, and the recent observations of Mr. Larsell who 

 came to the laboratory in 1913 as Fellow in Zoology. It was 

 agreed at the outset to review work already done, to extend it 

 and to collaborate in the publication of a paper on the develop- 

 ment of the avian lung. While, as to design, the investigation 

 originated with the senior author, as to execution, the observa- 

 tion has been unequally divided and it is only fair to say that the 

 details of the development of the bronchial tree, including the 

 air-sacs, and of the recurrent bronchi, are the result of the in- 

 vestigations of i\Ir. Larsell. The narrative and other embryo- 

 logical observations have fallen chiefly to the senior author. 



We have had the use of drawings and of manuscript theses 

 of Mr. G. H. A. Rech and of Miss Mary Head, former graduate 

 students working in the laboratory. The use of their sketches 

 has been helpful, but no personal observations have been bor- 

 rowed. Fifteen sketches by Mr. Rech, retouched and corrected, 

 have been rejoroduced in the body of the text. 



\\. A. L. 



' Coiiti-il)iit ion from the Zodloiiictil Lalioraf ory of Xortliwcstcrn riiivcrsity, 

 William A. Locy, Director. 



- Part II of til is jiaper will appear in the .Iul_\' issue. 



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