THE EAR. 



805 



and rounded, lying in a shallow depression in the head of the 

 inner pillar, thus resembling a ball and socket-joint (Fig. 163, 

 gia). The heads of the pillars, when seen from the surface, have 



Fio. 163. Section through the ductus cochlearis of a young dog : R-r f , Reissner's membrane ; Los 

 and Los', vestibular and tympanic plates of the osseous lamina ; gap, ganglion spirals ; n, fine nerves 

 passing through the habenula perforata at Jfn ; Cr, crista spiralis ; Lv, its vestibnla or upper lip ; 

 rm, Mt, m', the membrana tectoria (Corti's membrane) ; S#pi, recessus iriternus clothed with epithe- 

 lium ; fl and /a, inner and outer pillars of Corti , a and a", a", a", inner and outer hair-cells, between 

 the latter are seen the fl^sk-shaped cells, r, r, r ; Tn. nerve passing through the tunnel to reach one of 

 the outer hair-cells ; Hz, Henson's prop-cells : Sp, Zf/ zona pectinata ; gia, inner and outer beads of the 

 pillars of Corti : A'p, plate called phalynx. which, when joined with its neighbors, forms the lamina reti- 

 cularis, in which the ends of the hair-cells are supported; Lap, ligameutum spirale ; <S'w, stria vt 

 laris. After Lavdowsky. 



