THE PERIPHERAL NERVOUS SYSTEM 



IsPP 



FIG. 386. Three stages in the differentiation of the basal epithelium of the cochlear duct 

 to form the spiral organ (of Corti), internal spiral sulcus and labium vestibulare. A, Section 

 through the cochlear duct of an 8.5 cm. pig fetus (X 120); B, from a 20 cm. fetus (X 140); 

 C, from a 30 cm. fetus (near term) ( X 140). ep.s.sp., Epithelium of spiral sulcus; h.c., hair cells; 

 i.ep.c,, inner epithelial thickening; i.h.c., inner hair cells; i.pil., inner pillar of Corti; lab. vest., 

 labium vestibulare; limb, sp., limbus spiralis; m.bas., basilar membrane; m.tect., membrana 

 tectoria; m.vest., vestibular membrane; n.coch., cochlear division of acoustic nerve; o.ep.c., 

 outer epithelial thickening; o.h.c., outer hair cells; s.sp., sulcus spiralis; sc.tymp., scala tympani; 

 st.H., stripe of Hensen; t.sp. spiral tunnel. 



