116 



THE THIRD DAY. 

 FIG. 36. 



[CHAP. 



C/i- 



ac 



SECTION THROUGH THE INTERNAL EAR OF AN EMBRYONIC SHEEP (28 MM. 

 IN LENGTH). (Copied from Boettcher.) 



DM. Dura Mater. R.V. Recessus vestibuli. H.V.B. Posterior vertical 

 semicircular canal. U. Utriculus. H.B. Horizontal semicircular canal. 

 b. Canalis reuniens. a. Constriction by means of which the sacculus 

 hemisphericus S.R. is formed. /. Narrowed opening between sacculus 

 hemisphericus and utriculus. 0.0. Cochlea. <7.<7. Lumen of cochlea. 

 K.K. Cartilaginous capsule of cochlea. K.B. Investing mass. Oh. 

 Chorda dorsalis. 



