EXPLANATION OF THE PLATES. 



PLATE LXIX. 



Fig. 1. A portion of the mucous membrane of the olfactory 

 region of the sheep, showing the apertures of the 

 mucous follicles, and the pigment which covers its 

 surface. 80 diameters. 



Fig. 2. Blood-vessels of the pituitary region, injected. From 

 a preparation belonging to Mr. Quekett. 80 dia- 

 meters. 



Fig. 3. Denticulate lamina of the osseous zone of the la- 

 mina spiralis, seen on the vestibular surface. , free 

 edge of the teeth ; b, margin towards the axis of the 

 cochlea ; c, granular cells lying upon the same. 100 

 diameters. 



Fig. 4. Tympanic surface of a portion of lamina spiralis of 

 the cat. a, termination of the cochlear nerves at the 

 border of the osseous zone, with capillaries ramify- 

 ing over them ; b, inner clear belt of the mem- 

 branous zone; c, marginal capillary on the tym- 

 panic surface ; d, pectinate portion of the mem- 

 branous zone ; e, outer clear belt of membranous 

 zone, torn from the cochlearis muscle. 300 dia- 

 meters. After Todd and Bowman. 



Fig. 5. Inner view of cochlearis muscle of the sheep. , 

 line of attachment of membranous zone of lamina 

 spiralis, of which a portion, b, remains attached. 

 The surface below this line is in the scala tym- 

 pani ; the surface above, the scala vestibuli. c, 

 projecting columns, with intervening recesses, in 

 the vestibular part of the cochlearis muscle. After 

 Todd and Bowman. 



Fig 6. Plexiform arrangement of the cochlear nerves, seen 

 in the basal coil of the lamina spiralis, treated with 

 hydrochloric acid. There are no ganglion globules 



y 



