﻿THK 
  MIDDLE 
  EAR 
  AND 
  COLUMELLA 
  OF 
  BIRDS. 
  

  

  17 
  

  

  tissue 
  corpuscles 
  in 
  those 
  regions 
  (Fig. 
  4). 
  The 
  proliferation 
  

   of 
  tissue 
  to 
  form 
  the 
  hyoid 
  arch 
  takes 
  place 
  from 
  below 
  

   upwards 
  ; 
  this 
  is 
  shown 
  in 
  the 
  figures 
  where 
  the 
  more 
  ventral 
  

   portion 
  of 
  the 
  arch 
  (liij.) 
  is 
  thicker 
  than 
  the 
  more 
  dorsal 
  

   (stajJ.), 
  the 
  two 
  portions 
  passing 
  into 
  one 
  another 
  more 
  or 
  

  

  

  

  

  

  Pig. 
  4.— 
  Longitudinal 
  (slightly 
  honzontal) 
  section 
  tlirougli 
  liyoicl 
  region 
  

   of 
  five-day 
  chick. 
  

  

  less 
  suddenly 
  at 
  the 
  constriction^ 
  marked 
  cons., 
  fig. 
  4. 
  The 
  

   seventh 
  nerve 
  crosses 
  the 
  hyoid 
  arch 
  just 
  dorsal 
  to 
  the 
  con- 
  

   striction. 
  The 
  hyoid 
  and 
  auditory 
  capsule 
  proliferations 
  are 
  

   completely 
  separate^ 
  being 
  divided 
  by 
  a 
  space 
  Avhere 
  the 
  

   connective-tissue 
  corpuscles 
  are 
  much 
  more 
  thinly 
  scattered 
  

   It 
  is 
  seen 
  in 
  fig. 
  4 
  that 
  the 
  dorsal 
  or 
  proximal 
  portion 
  of 
  the 
  

  

  