]ME.  J.  L.  CLAEKE  ON  THE  INTIMATE  STEIJCTIJEE  OE  THE  BEAIN. 
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bundle  (P  ),  and  through  the  lamina,  with  the  further  side  of  the  outer  and  intervening 
bundle  (Q') ; and  so  on  through  the  rest  of  the  lamina;  but  although  these  latter  fibres 
appear  to  follow  the  course  of  the  convolutions,  I think  that  at  intervals  they  terminate 
in  cells.  At  the  antero-lateral  parts  of  the  sac,  the  axial  fibres  of  the  outer  bundles 
form  the  crust  of  the  olive  (see  figs.  28  et  seq.,  Plate  XVI.),  and  are  continuous,  on  the 
one  hand,  with  longitudinal  fibres  of  the  olivary  column,  and  on  the  other  hand,  with 
the  transverse  olivary  commissure  and  the  system  of  arciform  fibres.  On  the  left  side  of 
fig.  26,  Plate  XV.,  the  cells  of  the  lamina  are  faithfully  represented  in  situ,  and  in  con- 
nexion some  of  the  fibres.  The  olivary  bodies,  then,  are  intimately  connected  with  all 
the  surrounding  parts  of  the  medulla,  chiefly  through  the  arciform  system,  as  will  be 
more  fully  sho-^vn  further  on ; but  I have  never  been  able  to  trace  any  immediate  con- 
nexion between  the  cells  of  the  lamina  and  the  roots  of  the  nerves, — not  even  of  the 
h)’poglossal  nerves  which  pass  directly  through  it.  It  is  probable,  therefore,  that  the 
olivary  bodies  are  coordinating  centres  for  the  different  ganglia  or  nuclei  of  the  medulla 
oblongata. 
(30.)  The  description  thus  given  of  the  course  of  these  fibres  appears  to  be  highly 
important,  not  only  in  reference  to  the  structure  of  the  olive,  but  on  account  also  of  the 
light  it  would  seem  to  throw  on  the  structure  of  the  cerebral  hemisphere ; for  since  in 
both  these  organs  the  convolutions  are  formed  on  precisely  the  same  plan,  and  have 
precisely  the  same  relation  to  the  bundles  proceeding  from  the  nucleus,  it  is  highly  pro- 
bable that  the^^r^s  of  these  bundles,  in  both  cases,  have  the  same  destination  and  course; 
indeed  something  of  the  kind  in  the  cerebral  convolutions  has  been  already  made  out  by 
more  than  one  observer.  The  existence  of  the  outer  bundles  connecting  the  olive  with 
distant  parts  does  not  interfere  with  the  comparison. 
Eeceived  November  19,  1857. 
Corpora  Olivaria  of  Mammalia  and  Birds. 
(31.)  While  in  Mammalia  the  actual  existence  of  the  olivary  bodies  is  denied  by  many 
anatomists,  to  those  who  admit  them,  their  form,  structure,  and  connexions  may  be 
considered  as  unknoum.  I shall  therefore  describe  them  in  one  or  two  animals  of  this 
class. 
(32.)  In  the  Simiadce,  the  ohvary  bodies  are  prominent  at  the  surface,  but  vary 
somewhat  in  size  and  shape  in  different  genera.  In  Cercopitiiecus  and  Semnopithecus 
(figs.  38  and  39,  Plate  XVII.)  they  are  more  or  less  oval ; while  in  the  Wanderoo  (fig.  40), 
they  are  more  semilunar,  as  in  the  Bear  and  Seal  (fig.  41).  Figs.  7 and  8,  Plate  XII. 
represent  side  views  of  the  medulla  oblongata  of  the  Sheep,  and  figs.  3 and  4 exhibit  front 
views  of  the  medullse  of  the  Cat  and  Bog,  with  parts  of  the  cerebrum  and  cerebellum. 
As  it  ascends  from  the  points  of  the  anterior  pyramids,  the  medulla  oblongata  becomes 
much  enlarged,  and  rather  suddenly  forms  in  front  a projection  which  varies  in  extent 
in  different  animals.  At  the  base  of  the  pyramids  and  the  lower  border  of  the  pons  is  a 
