THE MEDULLA OBLONGATA OF LARVAL 

 AMBLYSTOMA 



C. JUDSON HERRICK 



From the Anatomical Laboratory of the University of Chicago 



FIFTY-SEVEN FIGURES 



CONTENTS 



Introduction 343 



The spinal cord 346 



The general structure of the medulla oblongata 348 



The sensory roots of the cranial nerves 354 



The lateral line roots of the facialis 355 



The lateral line roots of the vagus 358 



The roots of the VIII nerve 359 



The general cutaneous roots of the V, VII and X nerves 360 



The mesencephalic V root 361 



The visceral sensory roots of the VII, IX and X nerves 364 



Summary 366 



The terminal nuclei and sensory tracts related to the sensory roots of the cran- 

 ial nerves 367 



Summary 376 



The motor nuclei and tracts 377 



Summary 380 



General summary and discussion 381 



Literature cited 386 



INTRODUCTION 



The morphological pattern of the medulla oblongata of verte- 

 brates in general is well understood and the functional analysis 

 of the cranial nerve roots, their bulbar centers and chief correla- 

 tion tracts in different vertebrate types has been carried far enough 

 to show that this pattern is fundamentally similar throughout the 

 vertebrate phylum. The published observations on the internal 

 structure of the urodele rhombencephalon are, however, meagre 

 and quite inadequate to meet the requirements of a careful study 

 of the bulbar connections of the higher regions of these brains. 



343 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 24. NO. 4 



