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is  called  by  Stilling  the  accessory  olivary  nucleus,  and  the  latter,  the  large  nucleus  of 
the  pyramid.  I believe  they  are  both  parts  of  the  olivary  folds. 
(29.)  As  may  be  seen  in  fig.  23,  Plate  XIV.,  it  is  amongst  the  network  into  which  the 
anterior  cornu  is  resolved,  and  through  the  outer  portion  of  the  anterior  column  by 
which  it  was  surrounded,  that  the  olivary  body  is  developed.  Immediately  below  the 
inferior  rouirded  extremity  of  the  olive,  the  cells  are  not  ar-ranged  in  the  form  of  a con- 
volution, but  scattered  at  large  (fig.  24,  Plate  XV.).  Many  of  them  are  elongated  also 
in  the  directioir  of  the  column  and  are  distinctly  continuous  with  some  of  its  fibres ; but 
the  bundles  of  fibres  pass  on  to  the  sac  and  diverge  (see  fig.  24,  Plate  XV.).  The  super- 
ficial layer  beirds  forwards  and  outwards,  and  running  longitudinally  along  the  smiace, 
sends  some  of  its  fibres  in  successiorr  between  the  outer  convolrrtions  of  the  lamina, 
arrd  then  proceeds  onwards  through  the  pons ; the  bundles  of  the  deep  layer  spread  out 
iir  the  olive,  passing  through  and  between  the  remaining  convolutions,  and  forming 
a large  portion  of  the  central  nucleus.  In  relation  to  the  lamina,  the  coiu’se  and 
arrangement  of  the  fibres  of  the  sac  are  very  complicated,  and  not  easily  described  with 
perspicuity*.  Fig.  25,  Plate  XV.  represents  a series  of  convolutions  from  the  posterior 
wall  of  the  sac,  with  part  of  the  central  nucleus  (O,  O),  as  seen  in  a transverse  section. 
The  convolutions  are  turned  with  their  convexities  alternately  toivards  and  from  the 
nucleus  or  interior  of  the  sac,  and  the  concavity  of  each  is  occupied  by  a bundle  or  pro- 
cess of  fine  tubular  fibres,  which  diverge  within  it.  The  bundles,  then,  are  alternately 
within  and  ivithoict  the  cavity  of  the  sac,  but  a great  many  fibres  of  the  one  set  are  con- 
tinuous with  those  of  the  other  through  the  vesicular  lamina  or  wall.  They  assume  the 
form  of  the  convolutions,  and  sometimes  divide  into  two  or  three  branches,  which  receive 
convolutions  between  them.  For  convenience  of  description,  the  fibres  of  each  bundle 
may  be  dmded  into  two  sets.  On  selecting  an  inner  bundle  (P)  or  process  of  the  central 
nucleus  (O),  it  may  be  seen, — 1st,  that  the  fibres  at  its  centre  or  axis  proceed  m straight 
lines  nearly  to  the  summit  of  the  convolution,  where  some  of  them  terminate  in  ceils  of 
the  lamina,  and  some  form  a series  of  curves  or  tortuous  loops  between  them ; while 
others  pass  through  the  lamina  either  singly  or  in  small  bundles,  and  cross  each  other 
in  a tortuous  course  towards  the  posterior  part  of  the  medulla  (Q).  2ndly.  The  lateral 
fibres  of  the  bundle  are  successively  more  divergent  towards  its  base : some  of  them 
terminate  in  ceils ; but  the  rest  in  large  numbers  pass  through  the  lamina  to  the  next 
outer  and  inverted  bundle  on  each  side,  from  the  bases  of  which  they  partly  turn  round 
the  summit  of  the  convolution  to  form  a band  of  some  depth,  and  partly  diverge  to  the 
posterior  region  of  the  medulla  (Q),  where  they  cross  each  other  with  different  degrees 
of  obliquity  and  join  the  arciform  plexus  (see  fig.  36,  Plate  XVII.  V').  Traced  towards 
the  interior  of  the  sac,  the  fibres  near  the  middle  or  axis  of  the  bundle  (P)  diverge 
through  the  nucleus  (O,  O),  while  those  at  the  side  of  its  base  turn  round  the  extremity 
of  the  next  convolution  (R)  to  be  continuous  with  the  nearer  side  of  the  next  inner 
* It  lias  cost  me  extraordinary  time  and  trouble  to  arrive  at  a satisfactory  conclusion  on  tins  very  diffi- 
cult point ; and  I succeeded  only  by  a still  further  modification  of  my  method. 
