﻿THE 
  BRAIN 
  OF 
  THE 
  LOCUST. 
  231 
  

  

  of 
  the 
  pupa), 
  in 
  two 
  rows 
  when 
  fewer 
  in 
  number 
  than 
  in 
  the 
  adult. 
  The 
  

   superior 
  and 
  Larger 
  division 
  of 
  the 
  central 
  body 
  contains 
  the 
  series 
  of 
  

   what 
  we 
  may 
  call 
  unicellular 
  bodies, 
  sixteen 
  in 
  a 
  series. 
  The 
  lower 
  se- 
  

   ries 
  are 
  spherical 
  or 
  slightly 
  elongated, 
  and 
  rest 
  in 
  the 
  fibrous 
  partition 
  

   or 
  septum, 
  forming 
  the 
  floor 
  of 
  the 
  superior 
  division 
  of 
  the 
  central 
  body. 
  

   The 
  upper 
  row 
  of 
  bodies 
  are 
  cylindrical, 
  and 
  about 
  three 
  or 
  four 
  times 
  

   as 
  long- 
  as 
  thick. 
  They 
  are 
  separated 
  by 
  thin 
  fibrous 
  septa. 
  PL 
  XIV, 
  

   Fig. 
  2, 
  represents 
  the 
  central 
  body 
  enlarged 
  225 
  diameters. 
  When 
  we 
  

   examine 
  the 
  central 
  body 
  in 
  an 
  earlier 
  stage, 
  i. 
  e., 
  the 
  second 
  pupal 
  

   (PI. 
  XIV, 
  Fig. 
  3), 
  we 
  see 
  that 
  the 
  body 
  is 
  covered 
  above 
  by 
  a 
  stratum 
  of 
  

   nucleated 
  ganglion 
  cells 
  continuous 
  with 
  those 
  next 
  to 
  the 
  bottom 
  of 
  

   the 
  upper 
  furrow 
  ; 
  and 
  that 
  the 
  fibrous 
  septum 
  between 
  the 
  upper 
  and 
  

   lower 
  division 
  also 
  contains 
  small 
  cells. 
  These 
  cells 
  disappear 
  in 
  the 
  

   adult, 
  and 
  evidently 
  give 
  rise 
  to 
  the 
  fibers 
  which 
  take 
  their 
  place. 
  It 
  

   will 
  also 
  be 
  seen 
  that 
  the 
  "unicellular 
  bodies" 
  are 
  shorter, 
  more 
  cell- 
  

   like, 
  than 
  in 
  the 
  adult; 
  hence 
  they 
  seem 
  to 
  be 
  modified 
  ganglion 
  

   cells, 
  which 
  have 
  at 
  an 
  early 
  date 
  lost 
  their 
  nucleus 
  and 
  nucleolus. 
  My 
  

   observations 
  on 
  the 
  central 
  body 
  of 
  the 
  locust 
  agree 
  in 
  the 
  main 
  with 
  

   those 
  of 
  Newton 
  (compare 
  his 
  Fig. 
  9). 
  His 
  drawings 
  are 
  not 
  especially 
  

   clear 
  and 
  definite, 
  but 
  the 
  differences 
  appear 
  to 
  be 
  unimportant. 
  There 
  

   are 
  perhaps 
  two 
  (16 
  instead 
  of 
  "12 
  or 
  14") 
  more 
  cellular 
  bodies 
  in 
  the 
  

   locust 
  than 
  in 
  the 
  cockroach. 
  Unfortunately 
  my 
  sections 
  of 
  the 
  brain 
  of 
  

   the 
  cockroach 
  do 
  not 
  show 
  the 
  central 
  body. 
  Dietl 
  states 
  that 
  the 
  central 
  

   body 
  is 
  a 
  " 
  median 
  commissural 
  system." 
  This 
  description 
  we 
  would 
  

   accept 
  in 
  a 
  modified 
  sense. 
  We 
  have 
  shown 
  that 
  the 
  unicellular 
  bodies 
  

   and 
  the 
  cells 
  beneath 
  them 
  were 
  once 
  like 
  the 
  ganglion 
  cells, 
  but 
  that 
  

   they 
  have 
  lost 
  their 
  nuclei 
  and 
  nucleoli; 
  hence 
  the 
  functions 
  of 
  the 
  cen- 
  

   tral 
  body 
  must 
  be 
  unlike 
  that 
  of 
  an 
  ordinary 
  commissural 
  lobe. 
  Flogel 
  

   states 
  that 
  the 
  number 
  of 
  "sections," 
  or 
  what 
  I 
  call 
  unicellular 
  bodies, 
  

   is 
  eight 
  ; 
  we 
  have 
  counted 
  sixteen. 
  Both 
  Flogel 
  and 
  .Newton 
  appear 
  

   to 
  regard 
  these 
  bodies 
  as 
  simply 
  spaces 
  or 
  sections 
  between 
  fibrous 
  

   partitions 
  ; 
  but 
  it 
  would 
  appear 
  that 
  these 
  sections 
  are 
  really 
  modified 
  

   cells, 
  and 
  that 
  the 
  fibrous 
  septa, 
  are 
  possibly 
  the 
  cell- 
  walls, 
  somewhat 
  

   modified. 
  

  

  The 
  mushroom 
  bodies. 
  — 
  These 
  curious 
  organs 
  have 
  attracted 
  a 
  good 
  

   deal 
  of 
  attention 
  from 
  writers 
  on 
  the 
  brain 
  of 
  insects. 
  Dujardin, 
  in 
  1850, 
  

   first 
  drew 
  attention 
  to 
  them. 
  His 
  memoir 
  we 
  have 
  not 
  at 
  hand 
  to 
  refer 
  

   to, 
  but 
  as 
  stated 
  by 
  Xewton 
  328 
  — 
  

  

  Dujardin 
  pointed 
  out 
  that 
  in 
  some 
  insects 
  there 
  were 
  to 
  he 
  seen 
  upon 
  the 
  upper 
  

   part 
  of 
  the 
  hrain 
  certain 
  convoluted 
  portions 
  which 
  he 
  compared 
  to 
  the 
  convolutions 
  

   of 
  the 
  mammalian 
  brain, 
  and, 
  inasnmch 
  as 
  they 
  seemed 
  to 
  he 
  more 
  developed 
  in 
  those 
  

   insects 
  which 
  are 
  remarkable 
  for 
  their 
  intelligence, 
  such 
  as 
  ants, 
  bees, 
  wasps, 
  &c, 
  he 
  

   seemed 
  to 
  think 
  the 
  intelligence 
  of 
  insects 
  stood 
  in 
  direct 
  relationship 
  to 
  the 
  devel- 
  

   opment 
  of 
  these 
  bodies. 
  The 
  form 
  of 
  these 
  structures 
  is 
  described 
  by 
  the 
  same 
  au- 
  

   thor 
  as 
  being, 
  when 
  fully 
  developed, 
  as 
  in 
  the 
  bee, 
  like 
  a 
  pair 
  of 
  disks 
  upon 
  each 
  side, 
  

  

  328 
  On 
  the 
  Brain 
  of 
  the 
  Cockroach. 
  By 
  E. 
  T. 
  Newton. 
  Quart. 
  Journ. 
  Microscopical 
  Science, 
  July, 
  

   1879, 
  H, 
  pp. 
  341,342. 
  

  

  