388 



FISHES 



CHAP. 



mucus-connected, calcareous particles, as in Elasmobrauchs, or as 

 massive solid concretions in Teleosts, are present in relation with 

 the sensory areas of the utriculus, sacculus, and lagena. 



In a few marine and in a laree number of freshwater Teleosts 



riQ. 221.— Auditory organs of Fishes. A, of a typical Fish; B, of Myxine ; C, of 

 Ghimaera; and D, oi Perca. a.c, Anterior canal ; am', am", am'", ampullae ; am.n, 

 nerves to ampullae ; c, semicircular canal (iu Myxine] ; d.e, ductus endo-lymphaticus ; 

 h.c. horizontal canal; I, lagena; mc, macula ae u stica ;' m.s, macula acustica of 

 the sacculus ; n, nerves to an^.uUae ; ■;, external aperture of the ductus endo- 

 lymphaticus ; p.c, posterior canal ; s, sacculus ; s.e, sinus endo-lymphaticus ; sh, 

 superficial skin ; s.s, sinus superior ; u, ntriculus ; viii, auditory nerve. (From 

 Wiedersheim, after Retzius.) 



the auditory organ enters into a more or less intimate connexion 

 with the air-bladder by one of three different methods. The 

 first and simplest is by the apposition of the extremities of a 

 pair of caecal tubular prolongations from the air-bladder to the 



