author's abstract of this paper issued 

 by the bibliographic service, february 2 



THE MEMBRANOUS LABYRINTH AND ITS RELATION 



TO THE PRECOELOMIC DIVERTICULUM OF 



THE SWIMBLADDER IN CLUPEOIDS 



HENRY C. TRACY 



Department of Anatomy, University of Kansas 



TWENTY FIGURES 



CONTENTS 



Introduction 219 



Material and methods 220 



Terminology 220 



General histological structure of the swimbladder and the precoelomic 



diverticulum 222 



The perimeningeal tissue and the perilabyrinthine spaces 224 



The membranous labyrinth 229 



The function of the ear-swimbladder relation in Clupeoids 233 



Summary 241 



INTRODUCTION 



In a recent paper (Tracy, '20) I have described the Clupeoid 

 skull and cranial nerves from the point of view of their rela- 

 tions to the precoelomic diverticulum of the swimbladder. In 

 that paper is also included a summary of previous investigations 

 on the ear-swimbladder relation in Clupeoids. This present 

 paper is concerned primarily with the swimbladder diverticu- 

 lum and the membranous labyrinth and their relations to each 

 other and to the skull. Of particular interest is the macula acus- 

 tica utriculi, which has not been previously described and which 

 in Clupeoids is different in structure and relations from that in 

 other groups of animals. The probable physiological signifi- 

 cance of these structures is also discussed in this paper. 



The drawings were made by Mr. Leo Massopust, the depart- 

 ment artist at Marquette School of Medicine. 



219 



