ON THE DEVELOPMENT OF THE MEMBRANOUS LABY- 
RINTH AND THE ACOUSTIC AND FACIAL NERVES IN 
THE HUMAN EMBRYO. 
BY 
GEORGE L. STREETER, M.D., 
Associate, Wistar Institute of Anatomy. 
From the Anatomical Laboratory of Johns Hopkins University. 
WITH 2 PLATES AND 8 TEXT FIGURES. 
In the following paper some observations are reported concerning the 
embryonic morphology of the acoustic nerve and the development of 
the ganglion mass incorporated in its trunk. The differentiation of 
this latter mass, the ganglion acusticum, and its subdivision into the 
ganglion vestibulare and the ganglion spirale present several features of 
interest ; and deserving of especial attention is the additional light which 
the study of this process throws upon the question of nerve supply of 
the saccule, and the ampulla of the posterior semi-circular canal. It 
is found, namely, that these two portions of the membranous labyrinth 
are not supplied by the cochlear nerve, as described in English and 
German text books, but are supplied by the vestibular nerve, as has 
been maintained by some of the French writers. This brings all of the 
ampulle together with the utricle and saccule under control of the 
same nerve, and leaves the cochlear nerve as a specialized and distinct 
nerve for itself, supplying only the cochlear duct. This arrangement is 
one which should be gratifying to the physiologist, for it draws a 
definite line between that portion of the nerve complex which controls 
the analysis of sound and that which controls equilibrium. 
1Preliminary reports concerning this investigation were read, and the 
models demonstrated, at the International Congress of Anatomists at Geneva, 
August, 1905, and at the meeting of the American Association of Anatomists 
at Ann Arbor, December, 1905. 
AMERICAN JOURNAL OF ANATOMY.—VOL. VI. 
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