AUTHOR 8 ABSTRACT OF THIS PAPER ISSUED 

 BY THE BIBLIOGRAPHIC SERVICE, MARCH 27 



EXPERIJ^IENTS ON THE DEVELOPMENT OF THE CRA- 

 NIAL GANGLL4 AND THE LATERAL LINE SENSE 

 ORGANS IN AMBLYSTOMA PUNCTATUMi 



L. S. STONE 

 Osborn Zoological Laboratory, Yale University 



NINETY FIGURES 



CONTENTS 



Introduction 421 



Material, methods, and normal development 427 



Experimental 457 



A. Extirpation of placodes 459 



1. Removal of ophthalmic placode 459 



2. Removal of gasserian placode 462 



3. Removal of the preauditory placode and the supra-orbital pri- 



mordium 464 



4. Removal of infra-orbital, hyomandibular, ventral hyomandibular, 



and mandibular primordia 467 



5. Removal of the epibranchial placode of VII and surrounding 



ectoderm 467 



6. Removal of epibranchial placodes of IX and X and postauditory 



lateral-line primordia 471 



B. Removal of neural crest 474 



1. Contribution to mesodermal tissue 474 



2. Contributions to ganglionic components 483 



a. Contribution to V and VII 483 



b. Contribution to IX and X 485 



Discussion 487 



Summary 493 



Literature cited 495 



INTRODUCTION 



The experiments set forth in this paper were undertaken for 

 the purpose of extending our knowledge concerning the part which 

 placodes and neural crest play in the formation of cranial ganglia 

 and nerves, and also to determine, if possible, the extent of their 



^ Read before the American Association of Anatomists, March 25, 1921 . 



421 



