No. 4.— CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY 

 OF THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 

 COLLEGE. E. L. MARK, DIRECTOR. No. 203. 



The peripheral terminations of the eighth cranial nerve in vertebrates, 



especially in fishes. 



By R. C. Mullenix. 



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TABLE OF CONTENTS. 



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I. Introduction 215 



II. Historical review 216 



III. Material and methods 221 



IV. General anatomy and histology of the ear of Fundulus .... 227 

 V. Nervous structures 230 



A. In cristae acusticae 230 



B. In maculae acusticae 234 



C. In macula neglecta 237 



VI. Summary of observations 237 



VII. General discussion and conclusions 238 



VIII. Bibliography 245 



Explanation of Plates 250 



I. Introduction. 



Since 1891 much of the investigation and discussion carried on by 

 neurologists has been directed to the sohition of the question as to the 

 morphological units of which the nervous system is composed. The 

 conception that the nervous system is made up of cellular elements, 

 more or less independent of one another, which was in that year pro- 

 posed by Waldeyer ('91) in his formulation of the neurone concept, 

 has found wide acceptance, and stimulated investigations which have 

 greatly advanced the knowledge of the minute anatomy of the nervous 

 system. The theory has not escaped opposition, however, for a num- 

 ber of eminent men, among whom are Golgi, Apathy ('97), Nissl 

 (:03), and Bethe (:04), have vigorously attacked it; and there are not 

 a few at present who see in the fibrillar theory a worthy rival of the 

 neurone theory, and regard the neurofibril, and not the neurone, as 

 affording a fundamental basis for the understanding of the nervous 



system. 



