HISTOLOGY OF THE MEMBRANOUS LABYRINTH. 



89 



where the membranous canals adhere to the bones, the perios- 

 teum is feebly developed ; in the angular spaces, on the other 

 hand, where the canals separate from the bones, strong nu- 

 cleated fasciculi of connective tissue pass from the periosteum 

 to the external fibrous layer of the membranous semicircular 

 canals, and these ligamenta labyrinthi canaliculorum form the 

 essential means by ivhich the semicircular canals are retained 

 in position. In some cases there are two or more bands 



Fig. 298. 



Fig. 298. Utriculus and sacculus rotundus, drawn with the camera 

 lucida. 1, Utriculus ; 2, sacculus rotundus ; 3, macula acustica ; 

 4, ampulla ; 5, canalis communis . 



which enclose variously shaped spaces between them. These 

 spaces appear to be the transverse sections of small canals 

 which run along the ligaments to the principal membranous 

 canal. They may even be found in the neighbourhood of 

 the ampullae, but I do not think that any particular mor- 

 phological or physiological importance is to be attributed to 

 them. In the sacculi and ampullse, these ligaments, or rather 



