THE VERTEBRATE EAR. 345 



EXPLANATION OF PLATE V. 



Fig. I. A surface view (dorsal) of the organ of Corti of the Virginia Opossum. 

 a. X 630, b. X 3S0. a., the heads of the outer pillars of Corti prolonged into the 

 apical beaks o.p.h. and the outer face of the arch c.a. s., spaces between the heads 

 occupied by the first row of outer hair cells, b., surface view of the hair band. The 

 length and course of the hairs in four successive planes shown, h.c, hair cells. /., 

 lumen in the inner edge of the band, — the so-called structureless edge, l.k., outer 

 edge of band. 



Fig. 2. The caps of three hair cells from the organ of Corti of an adult Rabbit. 

 The basal ends of the auditory hairs remain attached to the cap, and are shown in 

 the figure only on one of the cell caps. Some of the hairs are much bent and curled, 

 owing to elastic rebound after the breaking strain had been applied. X 1400. 

 NaCl, glycerine preparation. 



Fig. 3. A view from the dorsal surface of the organ of Corti of a Rabbit newly 

 born, showing the long hairs of the organ of Corti in connection with their cells. 

 The cells of the first two rows of outer hair cells are the only ones shown in the 

 figure. X 850. The brown background represents the body of the hair band, and 

 at h.b. the course of the upper layer of fibres or hairs is shown, h.c, hair cells. In 

 the figure " Cortis fillars " should of course read " Corti's pillars," the double outline 

 indicating the position of the row of pillar heads. 



Fig. 4. A portion of a tangential section of the organ of Corti of an adult Rabbit, 

 showing the manner in which the hairs of the hair cells pass off to the hair band. 

 The structure of the hair cells is shown in two of them. X 1400. s.c, supporting 

 cells, nl.cl.f., the nucleo-capillary fibres connecting the roots of the hairs with the 

 nucleus. 



Fig. 5. Three hair cells from the adult organ of Corti of the Rabbit, showing the 

 " Hensenschenkorper " and its relation to the auditory hairs on the one hand and 

 the nucleus on the other. X 1400. In a, at do is shown the manner of entrance or 

 attachment of the nucleo-capillary filaments to the nucleus. They cross a shrinkage 

 space in the protoplasm just before attaching. 



Fig. 6. A perspective view of the developing organ of Corti of a Pig embryo 

 10 inches in length. Showing the manner in which the auditory hairs rise from the 

 surface of the epithelial cells. X 114- l.e.r. and s.e.r., large and small epithelial 

 ridges. 



Fig. 7. An auditory cell from the organ of Corti of an adult Rabbit, showing the 

 relation of the hairs to the cell, and especially its nucleus, as in Fig. 5. X 1400. 

 The hair filaments are continued from without through the cell. The " Hensen 

 Korper" lies at the base of the apical funnel of the celL The nerve enters the side 

 of the cell. The figure does not intend to convey the idea that the nerve enters the 

 nucleus. 



Fig. 8. A nucleus of an auditory cell from the same organ of Corti, showing the 

 capillary filaments of the peripheral and neural poles of the nucleus and two lateral 

 stainable bodies. X 1400. 



Fig. 9. Transverse section of the developing organ of Corti of a Pig embryo 

 %\ inches in length. The pillar cell has not yet divided. X 380. The hairs of the 



