﻿G6i 
  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  . 
  

  

  half 
  of 
  tbe 
  body 
  appeared 
  to 
  be 
  getting 
  annulated, 
  whicli 
  was 
  so 
  by 
  the 
  twenty-Orst 
  day. 
  

   * 
  * 
  * 
  On 
  the 
  twenty-second 
  day 
  the 
  annulations 
  of 
  the 
  anterior 
  half 
  of 
  the 
  body 
  were 
  

   very 
  distinct, 
  the 
  posterior 
  half 
  was 
  also 
  becoming 
  annulated, 
  and 
  near 
  its 
  extremity 
  I 
  

   for 
  the 
  first 
  time 
  observed 
  an 
  anal 
  orifice 
  and 
  one 
  to 
  four 
  small 
  epidermal 
  spines. 
  On 
  

   the 
  twenty-fourth 
  day, 
  the 
  tubular 
  clavate 
  organ 
  before 
  mentioned, 
  occui^ying 
  the 
  an- 
  

   terior 
  part 
  of 
  the 
  alimentary 
  canal, 
  was 
  alternately 
  protruded 
  and 
  retracted 
  as 
  a 
  pro- 
  

   boscis. 
  The 
  proboscis, 
  when 
  fully 
  protruded, 
  brought 
  into 
  view 
  at 
  its 
  base 
  a 
  second 
  

   circle 
  of 
  tentacular 
  filaments 
  within 
  the 
  first. 
  On 
  the 
  twenty-sixth 
  day 
  the 
  embryo, 
  

   when 
  pressed 
  from 
  the 
  egg, 
  progressed 
  forward 
  by 
  moving 
  "the 
  posterior 
  half 
  of 
  'its 
  

   body 
  from 
  side 
  to 
  eide, 
  and 
  it 
  alternately 
  protruded 
  and 
  retracted 
  the 
  proboscis 
  and. 
  i 
  

   the 
  two 
  circles 
  of 
  tentacular 
  filaments. 
  When 
  all 
  the 
  organs 
  were 
  retracted 
  the 
  head 
  I 
  

   presented 
  a 
  truncate 
  or 
  depressed 
  surface, 
  and 
  in 
  their 
  protrusion 
  the 
  extremities 
  of 
  the 
  f 
  ■ 
  

   outer 
  circle 
  of 
  tentaculis 
  and 
  the 
  end 
  of 
  the 
  proboscis 
  first 
  became 
  visible 
  ; 
  as 
  these 
  

   advanced, 
  the 
  second 
  circle 
  of 
  tentaculm 
  appeared, 
  and 
  when 
  the 
  proboscis 
  was 
  en- 
  1 
  

   tirely 
  protruded, 
  the 
  outer 
  tentaculai 
  were 
  deeply 
  reflected 
  upon 
  the 
  outside 
  of 
  the 
  

   body, 
  and 
  the 
  inner 
  circle 
  projected 
  obliquely 
  outward 
  and 
  upward. 
  (See 
  also 
  Leidy's 
  

   figures 
  and 
  description 
  in 
  the 
  American 
  Entomologist, 
  ii, 
  p. 
  196.) 
  

  

  It 
  is 
  evidently 
  this 
  species 
  whose 
  habits 
  Dr. 
  Leidy 
  further 
  describes 
  

   in 
  his 
  " 
  Flora 
  and 
  Eauna 
  within 
  Living 
  Animals."* 
  I 
  quote 
  as 
  follows 
  

   from 
  this 
  work 
  : 
  

  

  The 
  grasshoppers 
  in 
  the 
  meadows 
  below 
  the 
  city 
  of 
  Philadelphia 
  are 
  very 
  much 
  11 
  

   infested 
  with 
  a 
  species 
  of 
  Gordius 
  probably 
  the 
  same 
  as 
  the 
  former, 
  but 
  in 
  a 
  different 
  "I 
  

   stage 
  of 
  development. 
  More 
  than 
  half 
  the 
  grasshoppers 
  in 
  the 
  locality 
  mentioned 
  

   contain 
  them 
  ; 
  but 
  those 
  in 
  drier 
  places, 
  as 
  in 
  the 
  fields 
  west 
  and 
  north 
  of 
  Philadel- 
  

   phia, 
  are 
  quite 
  rarely 
  infested, 
  for 
  I 
  have 
  frequently 
  opened 
  large 
  numbers 
  without 
  

   finding 
  one 
  worm. 
  

  

  The 
  number 
  of 
  Gord'ii 
  in 
  each 
  insect 
  varies 
  from 
  one 
  to 
  five, 
  their 
  length 
  from 
  3 
  inches 
  

   to 
  a 
  foot; 
  they 
  occupy 
  a 
  position 
  in 
  the 
  visceral 
  cavity, 
  where 
  they 
  lie 
  coilt^d 
  among 
  

   the 
  viscera, 
  and 
  often 
  extend 
  from 
  the 
  end 
  of 
  the 
  abdomen 
  forward 
  through 
  the 
  thorax 
  

   even 
  into 
  the 
  head. 
  Their 
  bulk 
  and 
  weight 
  are 
  frequently 
  greater 
  than 
  all 
  the 
  soft 
  

   parts, 
  including 
  the 
  muscles, 
  of 
  their 
  living 
  habitation. 
  Nevertheless, 
  with 
  this 
  rela- 
  

   tively 
  immense 
  mass 
  of 
  parasites, 
  the 
  insects 
  j 
  amp 
  about 
  almost 
  as 
  freely 
  as 
  those 
  not 
  

   infested. 
  

  

  The 
  worms 
  are 
  milk-white 
  in 
  color, 
  and 
  undivided 
  at 
  the 
  extremities. 
  The 
  females 
  

   are 
  distended 
  with 
  ova, 
  but 
  I 
  have 
  never 
  observed 
  them 
  extended. 
  

  

  When 
  the 
  bodies 
  of 
  grasshoppers, 
  containing 
  these 
  eutozoa, 
  are 
  broken 
  and 
  laid 
  upon 
  

   moist 
  earth, 
  the 
  worms 
  gradually 
  creep 
  out 
  and 
  pass 
  below 
  its 
  surface. 
  Some 
  speci- 
  

   mens 
  which 
  crawled 
  out 
  of 
  the 
  bodies 
  of 
  grasshoppers 
  and 
  penetrated 
  into 
  earth 
  con- 
  

   tamed 
  in 
  a 
  bowl, 
  last 
  August, 
  have 
  undergone 
  no 
  change, 
  and 
  are 
  alive 
  at 
  the 
  present 
  

   time 
  (November, 
  1852). 
  

  

  In 
  the 
  natural 
  condition, 
  when 
  the 
  grasshoppers 
  die, 
  the 
  worms 
  creep 
  from 
  the 
  body 
  

   and 
  enter 
  the 
  earth, 
  for^ 
  suspecting 
  the 
  fact, 
  I 
  spent 
  an 
  honr 
  looking 
  over 
  a 
  meadow 
  

   for 
  dead 
  grasshoppers, 
  and, 
  having 
  discovered 
  five, 
  beneath 
  two 
  of 
  them, 
  several 
  

   inches 
  below 
  the 
  surface, 
  I 
  found 
  the 
  Gordii 
  which 
  had 
  escaped 
  from 
  the 
  corpse. 
  

  

  Some 
  of 
  the 
  worms 
  pat 
  in 
  water 
  lived 
  for 
  about 
  four 
  weeks, 
  and 
  then 
  died 
  from 
  the 
  

   growth 
  of 
  Addya 
  jirolifera. 
  What 
  is 
  their 
  cyclical 
  developaient 
  ? 
  

  

  The 
  history 
  of 
  the 
  Gordius 
  aquaticns 
  has 
  been 
  mostly 
  cleared 
  up 
  by 
  A. 
  

   Villotjt 
  and 
  the 
  following 
  account 
  is 
  condensed 
  from 
  his 
  memoirs: 
  

  

  The 
  eggs 
  (Plate 
  LXTII, 
  Fig. 
  7, 
  a) 
  are 
  laid 
  in 
  long 
  chains; 
  they 
  are 
  white, 
  

   and 
  excessively 
  numerous. 
  The 
  yolk 
  undergoes 
  total 
  segmentation. 
  

   (Plate 
  LXIII, 
  Fig, 
  7, 
  h.) 
  At 
  the 
  close 
  of 
  this 
  period, 
  when 
  the 
  yolk 
  is 
  sur- 
  

   rounded 
  by 
  a 
  layer 
  of 
  cells, 
  the 
  germ 
  elongates 
  at 
  what 
  is 
  destined 
  to 
  

   be 
  the 
  bead-end, 
  this 
  layer 
  pushes 
  in, 
  forming 
  a 
  cavity, 
  and 
  in 
  this 
  state 
  

   itiscalleda 
  "gastruW 
  (Plate 
  LXIII, 
  Fig. 
  7, 
  c.) 
  Bvthistimetheembryo 
  

   becomes 
  pear-shaped 
  (Fig. 
  7, 
  d)-, 
  then 
  it 
  elongates. 
  Subsequently 
  the 
  

   internal 
  organs 
  of 
  digestion 
  are 
  formed, 
  together 
  with 
  three 
  sets 
  of 
  stiff, 
  

   spine-like 
  appendages 
  to 
  the 
  head, 
  while 
  the 
  body 
  is 
  divided 
  by 
  cross-lines 
  

   into 
  segments. 
  The 
  head 
  lies 
  retracted 
  within 
  the 
  body. 
  (Fig. 
  7, 
  e.) 
  

  

  In 
  hatching, 
  it 
  pierces 
  the 
  egg 
  membrane 
  by 
  the 
  aid 
  of 
  its 
  cephalic 
  

   armature, 
  and 
  escapes 
  into 
  the 
  water, 
  where 
  it 
  passes 
  the 
  early 
  part 
  of 
  

  

  * 
  Smithsonian 
  Contributions 
  to 
  Knowledge, 
  v. 
  1853. 
  

  

  tMunographie 
  des 
  Drtigouneaux 
  (Genre 
  Gordius 
  Dnjardin), 
  par 
  A. 
  Villot. 
  (Archives 
  

   de 
  Zoologie 
  exp6rimentale 
  et 
  g6u6rale, 
  tome 
  3, 
  No. 
  1, 
  2, 
  1874, 
  Paris.) 
  

  

  