438 



THE SENSORIAL FUNCTIONS. 



pansion, termed the Utricle (u). The Sacculus 

 (s) has, m like manner, a posterior appendage 

 (c) termed the Cysticule. The hard calcareous 

 bodies (o, o, o) are three in number ; and the 

 branches of nerves (i, i, i) by which they are 

 suspended in the fluid contained in the mem- 

 branes, are seen passing into them ; while the 

 ampullae are supplied by other branches (n,n,n). 



In all the osseous fishes the labyrinth is not en- 

 closed in the bones of the cranium, but projects 

 into its cavity ; but in the larger cartilaginous 

 fishes, as the ray and shark tribes, it is sur- 

 rounded by solid bone, and is not visible within 

 the cranium. In these latter fishes, we first 

 meet with a rudiment of the meatus, in a passage 

 extending from the inner side of the vestibule, 

 to the upper and back part of the skull, where 

 it is closed by a membrane, which is covered by 

 the skin. 



