An American text-book of physiology . et of flattened cells bywhich the rest of the ampulla is auditory cells(Fig. 279) are said tobe of two kinds—t)ne, cylindrical inshape and reaching only part way tothe basement membrane, the hair-cells;the other, narrow and elongated, thesupporting or sustentacular cells. The former are peculiar in the fact thatfrom their free ends there project long, stiff, hair-like processes. The fila-ments of the ampullary-nerve branches pass through the cristas and encirclethe bodies of the hair-cells. The cells covering the maculee acusticce haveessentially
An American text-book of physiology . et of flattened cells bywhich the rest of the ampulla is auditory cells(Fig. 279) are said tobe of two kinds—t)ne, cylindrical inshape and reaching only part way tothe basement membrane, the hair-cells;the other, narrow and elongated, thesupporting or sustentacular cells. The former are peculiar in the fact thatfrom their free ends there project long, stiff, hair-like processes. The fila-ments of the ampullary-nerve branches pass through the cristas and encirclethe bodies of the hair-cells. The cells covering the maculee acusticce haveessentially the same structure as those just described, though in the maculaethe auditory hairs are shorter than in the cristie. Seated on the free surfaceof the macular epithelium is a fibrous mass which is said to be a normalstructure, and not, like a somewhat similar mass found covering the crista^ inpost-mortem sections, a coagulum due to the method of preparation. Im-bedded in the membrane over the maculae of both saccule aud utricle are. Fig. 279.—Diagram showing the epithelial cells ofa macula or a crista (after Foster): 1, cylinder orhair-cell; 2, the same, enveloped in a nest of nerve-fibrils ; 3, 4, 5, forms of rod- or spindle-cells. THE SENSE OF HEARING. 819 small crvstals, oioJUhs or ofocouia, composed chiefly of carlx>nate of lime. Oto-conia are also found less constantly in the ampullai and even in the peri-lymph space of the cochlea. In fishes there are large masses of calcareousmatter, otoliths, attached to the wall (»f the auditory sac. General Anatomy of the Cochlea.—]5y far the most complex structure ofthe ear is found in the cochlea (PI. 2, Figs. 1,3, 4; Figs. 275-278). The bonycochlea continues from the anterior wall of the vestibule, and in the upright posi-tion of the head the axis of the modiolus is nearly horizontal, pointing, from base
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