author's abstract of this paper issued 

 by the bibliographic service, december 27 



THE NERVOUS SYSTEM OF A TWO-HEADED PIG 



EMBRYO 



MABEL BISHOP 



Anatomical Laboratory of the University of Chicago 



TWENTY FIGURES 



CONTENTS 



Introduction ^'^ 



Description of the material 381 



Method of study and terminology used 384 



Description of the nervous system 388 



Spinal cord and spinal nerves 388 



Sympathetic nervous system 388 



In the cervical region 388 



In the head 390 



The brain 394 



Cranial nerves 399 



Superficial origin and peripheral distribution of the nerves of the 



outer (normal) sides of the teratological head 399 



Superficial origin and peripheral distribution of the nerves of the 



median (conjoined) region 408 



The median isolated ganglion 411 



Central connections of the cranial nerves and the associated fiber tracts. 414 



In the normal regions of the teratological head 414 



In the conjoined regions 416 



The rostral cranial nerve-mass, its associated nerves and fiber tracts 416 



The caudal cranial nerve-mass, its associated nerves and fiber tracts 418 



Acknowledgments 4-U 



Summary 4-U 



Bibliography • • • ^^ 



INTRODUCTION 



The present investigation was stimulated by an earlier compara- 

 tive study of the circulatory system in young teratological speci- 

 mens of the laterally symmetrical dicephalous type occurring 

 free in nature (Bishop, '08). This was an intensive study of a 

 single system, chosen because it appears early in embryonic life, 



379 



