THE DEVELOPMENT OF THE HUMAN PHARYNX 



I. THE PHARYNGEAL DERIVATIVES 



B. F. KINGSBURY 



From the Department oj Histology and Embryology, Cornell University, Ithaca, N. Y . 



THIRTY-FOUR FIGURES (fIVE PLATES) 



CONTENTS 



Introduction 329 



Historical 334 



Nomenclature 334 



Material and methods 335 



Morphological plan of the pharynx 335 



Developmental transformations of the pharynx 339 



Thyreoid 343 



Complex III 345 



Complex IV 348 



The epibranchial placodes 354 



Larynx 359 



Pharyngeal derivatives 359 



Thymus 360 



Parathyreoids 371 



Thyreoid 373 



Ultimobranchial body 374 



Endocrine organs 374 



Bibliography 383 



INTRODUCTION 



The following study began as an examination of the trans- 

 formation of the second branchial or pharyngeal pouch. ^ Of 

 the branchial pouches that appear in the development of the 

 embryonic pharynx of man, the second, and the second alone, 



1 The problem was suggested to the writer by the late Dr. Charles S. Minot, 

 and was begun in his laboratory during a sabbatic leave in 1911. It is a pleasure 

 to acknowledge the generous help from that laboratory, and particularly the 

 kindly interest and suggestions of Dr. Minot and Dr. F. T. Lewis. 



329 



THE AMERICAN JOURNAL OP ANATOMY, VOL. 18, NO. 3 



November, 1915 



