Integrative Systems 



211 



auditory mechanisms which serve for more direct and effective trans- 

 mission of external vibrations into the internal ear. The equilibratory 

 mechanism of the ear shows little change in structure throughout the 



Fig. 182. Diagram of the membranous 

 labyrinth of a vertebrate, the sensory 

 areas dotted, (ac) Anterior semicircular 

 canal; (ap) ampullae; (ca) cristae acus- 

 ticae in the ampullae; (de) ductus endo- 

 lymphaticus; (he) horizontal (external) 

 canal; (/) lagena; (ml, mn, ms, mil) respec- 

 tively macula lagenae, m. neglecta, m. 

 sacculi, and m. utriculi; (pc) posterior 

 semicircular canal; (s) sacculus; (se) 

 saccus endolymphaticus; (sue) sacculo- 

 utricular canal; (u) utriculus. (Courtesy, 

 Kingsley: "Comparative Anatomy of 

 Vertebrates," Philadelphia, The Blakis- 

 ton Company. ) 



vertebrate series. The auditory mechanisms of amphibians, reptiles 

 and birds, and mammals show progressive development culminating 

 in mammals. 



PROPRIOCEPTORS 



Afferent fibers belonging to cells situated in cranial and spinal 

 ganglions pass into many of the deep tissues of the body, ultimately 



