THE INNERVATION OF THE AUDITORY EPI- 
THELIUM OF MUSTELEUS CANTS,, De Kay: 
ALBRO D. MORRILL. 
CONTENTS. Pack 
VI EI 0 TT be ce ee Ey eee Bs te es see ise vss ube 3bs cds cdogeusnbenecmepestesbieppesoeuoeecete 57 
ti Jrecent work on anditory epitheliwnn.oi:.b nes ceseecnsesseecepacestoramescne 57 
Ze INeKVeleMCIN gS INMGROS?S) LOWE UC sas: -seeye ce soe een sano nescence eee) OG 
PLEO Bi et ope as oa cases ee SER Senn ose coca aee poiren eae dune oonent darstenanconackaae ty OF 
Ill. JLnnervation of Auditory Epithelium tn Musteluts...........ceeeececceccceeeesees 68 
MN SLA PISACLE SESE EE AERC Ory ET ee er ee ee ee eee ee nutbeaeereceerass 71 
I. Historical. 
1. Recent work on auditory epithelium. — The application of 
the methods of Ehrlich and Golgi in their original and variously 
modified forms to the study of the auditory epithelium has 
greatly increased our definite knowledge of its innervation. 
Although there is considerable general uniformity in the 
results obtained by different observers, there are several dis- 
puted points, particularly in the interpretation of the results 
obtained. One of these which is of the greatest importance is 
the exact relation of the terminal branches of the nerve fibers 
to the auditory or hair cells. 
The numerous investigations carried out by Retzius by the 
old methods, as well as by the most recent, have led me to give 
a brief statement of the results of his earlier observations 
before considering more recent conclusions. 
In his great work, Retzius ('84) states that in general he was 
able to trace the nerves into the auditory epithelium and follow 
the naked nerve fibers between the basal layers of the support- 
1 I wish to express my indebtedness to Dr. Howard Ayers, at whose suggestion 
the work was undertaken; also to the Director of the Marine Biological Laboratory 
at Woods Holl, Mass., for many privileges enjoyed during the progress of the work. 
