No. I.] 



THE VERTEBRATE EAR. 



31 



outline seen from above, but is decidedly oval seen from the 

 side. The concave floor (from within) supports the macula 

 utriculi and is carried over into the mouths of the ampullae of 

 the anterior and horizontal canals. The macula utriculi covers 

 most of the floor and is irregularly oval, being very much larger 

 at one end than at the other. The sensory hairs are very long 

 and support a layer of otolithic bodies. 



Alligator (Cut 9). 



The utriculus in this reptile has assumed a tubular form, and, 

 as compared with the enlarged sacculus, no longer appears as a 



Ctit 9. — The right internal ear of 

 Alligato7' mississippiensis, seen from 

 the outer face. Figure after G. Ret- 

 zius. The figure outlines do not 

 bring out the relations of the parts 

 distinctly, and only the more impor- 

 tant parts are lettered, ac, auditory 

 nerve; (5, pars basilaris cochlese auct.; 

 c, anterior canal; ch, external canal; 

 f/, posterior canal; /, lagena; w', cris- 

 tje acusticse of the ampullae; s, sac- 

 culus. 



Cut TO. — The right internal 

 ear of Turdus imisica, seen from 

 the inner or neural face. Figure 

 after G. Retzius. The letters are 

 placed only on those parts of the 

 organ plainly visible in the figure. 

 ac, acoustic nerve ; c, anterior 

 canal; ch, external canal; cp, pos- 

 terior canal; d, ductus endolym- 

 phaticus; /, lagena; nis, macula 

 sacculi; n, lagenar nerve; «' cris- 

 tse acusticje of the ampullae. 



chamber of equal value, structurally and functionally, with the 

 latter. 



