394 DEVELOPMENT OF ORGANS IN MAMMALIA. [CHAP. 

 Fig. 131. 



MM 



Section through the Internal Ear of an Embryonic 

 Sheep 28 mm. in length. (After B6ttcher.) 



D.M. dura mater ; R. V. recessus labyrinthi ; H. V.B. posterior 

 vertical semicircular canal ; U. utriculus ; H.B. horizontal 



