294 ANIMAL MECHANISM. 



FIG. 5. 



Explanation of Figure 5. 



In this, the bony case of the labyrinth, has had one half cut 



away to exhibit the interior. 



a to I The upper part of the cochlea; aa, the thickness of its 

 external shell in a foetus of eight months ; bed, the lamina spira- 

 lis; be, scala vestibuli ; efghi, the scala tympani. Here is seen 

 the bony lamina spiralis ; b its origin ; d its termination in a little 

 hook, termed hamulus : k the opening of the infnndibulum, where 

 the scalae communicate ; I the opening of the aqueduct, or drain 

 ol the fluids from the cochlea. 



m tog The under half of the vestibulum ; m the thickness of its 

 case in the foetus ; n the fovea or round pit ; o an oval pit ; p a 

 ridge between them ; q opening of the aquseductus vestibuli. 



r,g,lc,l The canals divided ; r the thickness of their case in 

 the infant; g the posterior; / exterior semicircular canal ; 1 open- 

 ing of the big end of the posterior canal ; 2 opening of the large 

 end of the superior ; 3 the opening common to their united tubes ; 



4 the larger end; 5 the contracted opening of the external canal. 



OSSICULA AUDITUS. 



Perhaps there is no insulated portion of an animal, 

 that more clearly and satisfactorily evinces superhuman 

 design, than the figure and articulations of the four ear 



