The functions of the ear as at present known to the comparative physiologist are grouped as the acoustic and the non-acoustic. The cochlea is supposed on very good grounds to have to do with the acoustic functions, and the organs of the semicircular canals on equally good evidence are thought to have to do with such of the non-acoustic functions as equilibration and orientation. Just what the functions of the organs of the ear sacs are is not certainly known. These facts are of importance when we consider the attempts made by Alexander and Kreidl to correlate the various peculiarities of behavior shown by the dancer with the structural facts which their work has revealed. This correlation is indicated schematically below. The physiological facts to be accounted for in terms of structure are presented in the first column, and the anatomical facts which are thought to be explanatory, in the second (2 p. 539). FUNCTION 1 Lack of sensitiveness to auditory stimuli. {Structure 1,2,3 below} 2 Defective equilibrational ability. {Structure 4,5,6 below} 3 Lack of turning dizziness. {Structure 4,5,6 below} 4 Normal reactions to galvanic stimulation. (not related in table to any Structure) STRUCTURE 1 Destruction of the papilla basilaris cochleae, etc. 2 Diminution of the inferior branch of the eighth nerve. 3 Marked degeneration of the ganglion spirale. 4 Destruction of the macula sacculi. 5 Diminution of the branches and roots of the superior and middle branches of the eighth nerve. 6 Diminution of both ganglia vestibulii and of the nerve cells. Alexander and Kreidl themselves believe that the partial deafness of the dancers (for they admit that the total lack of hearing has not been satisfactorily proved) is due to the defective condition of the cochlea. They account for the imperfect equilibrational ability of the animals by pointing out the structural peculiarities of the sacculus, the vestibular ganglia, and the peripheral nerves. Similarly, the lack of dizziness they suppose to be due to the diminution of the fibers of the nerves which supply the canal organs, the atrophied condition of the vestibular ganglia, and a disturbance of the peripheral sense organs. Furthermore, there are no anatomical facts which would indicate a lack of galvanic dizziness (2 p. 552). Despite the fact that they seem to explain all the functional peculiarities of the dancer, the statements made by Alexander and Kreidl are neither satisfying nor convincing. Their statements concerning the structure of the ear have not been verified by other investigators, and their correlation of structural with functional facts lacks an experimental basis.