VESSELS OF THE LABYRINTH. 



Ill 



rounded extremity. They are surrounded by the branching axis-cylinders of the 

 nerve-fibres which penetrate into the epithelium ; the medullary sheath disappears 



Fig. 123. LONGITUDINAL SECTION OF AN AMPULLA ' THROUGH THE GKISTA ACUSTICA. 



SEMI-DIAGRAMMATIC (E.A.S.). 



'.amp, cavity of the ampulla; sc. c, semicircular canal opening out of it; c, connective tissue 

 attached to the wall of the membranous ainpulla and traversing the perilymph ; e e, flattened epithelium 

 of ampulla ; h, auditory hairs projecting from the columnar cells of the auditory epithelium into the 

 cupula, cup. term. ; v, limit of the auditory epithelium on the crista ; n, nerve-fibres entering the base 

 of the crista and passing into the columnar cells. 



as the fibres enter the epithelial layer, and the axis-cylinders ramify amongst the 

 cells, but there does not appear to be any actual continuity between the terminal 

 arborizations of the nerve fibres (fig. 125) and the hair-cells. 



_ - 

 J. 



Fig. 124. SECTION OF THE MACULA ACUSTICA OF THE RECESSUS UTRICULI, HUMAN. 

 (GK Retzius.) Magnified. 



n.utr., bundles of the utricular branch of the eighth nerve ; A, hair-cells ; p.l.s., perifymphatic 

 space. 



Between and beneath the columnar cells other cells are met with of a different 

 character. They take the form of long and comparatively rigid fibres (fibre-cells of 

 Retzius) which extend through the whole thickness of the epithelium, and are pro- 

 vided at one part of their course with a nucleated enlargement. This is always 



