author's adsthact of this papeh issued by 

 the binliographic service, september 28 



THE FATE OF THE ULTIMOBRANCHIAL BODIES IN 

 THE PIG (SUS SCROFA)i 



J. A. BADERTSCHER 



Deparlmenl of Anatomy, Indiana University School of Medicine, Bloomington, 



Indiana 



FOUR PLATES 



I. Introduction ^ ' 89 



II. Historical 90 



III. Material and methods 92 



IV. Description of stages 93 



V. Summary and discussion Ill 



VI. Conclusions 119 



VII. Bibliography 121 



I. INTRODUCTION 



The fate of the ultimobranchial bodies is one of the many un- 

 settled questions associated with the development of the thyroid 

 gland. While most of the results of the considerable amount of 

 investigation that has been done in recent years on these struc- 

 tures in various mammalian species have led to the interpretation 

 that they do not contribute to the structural elements of the 

 thyroid gland, there is still a diversity of views as to their actual 

 fate. The variety of views expressed in the literature in regard 

 to their fate in mammals is apparently due to several factors 

 among which may be mentioned: (1) the possibility of a variable 

 developmental behavior of these structures in different mammalian 

 types, (2) inadequate series of successively older embryonic stages 

 (especially embryos of larger mammals) , and (3) faulty technique 

 (principally poor fixation of the thyroid gland in the older em- 

 bryos of the larger mammals, especially man). 



1 Some of the younger stages used in this study were prepared during the 

 summer of 1914 while a guest in the Department of Histology and Embryology in 

 Cornell University. I wish to express my appreciation to Prof. B. F. Kingsbury 

 for the facilities so generously extended to me during that time. 



89 



