﻿ECHIUROID 
  WORMS 
  OF 
  NOKTH 
  PACIFIC 
  — 
  FISHER 
  271 
  

  

  crop 
  and 
  gizzard 
  of 
  chilcnsis 
  by 
  direct 
  comparison 
  are 
  definilcly 
  

   longer 
  than 
  in 
  caupo 
  by 
  about 
  25 
  percent. 
  

  

  The 
  stomach 
  (crop 
  2 
  of 
  Scitz) 
  corresponds 
  to 
  that 
  of 
  Thalasscma, 
  

   and 
  the 
  mucosa 
  lias 
  about 
  12 
  distinct 
  longiseries 
  of 
  compressed 
  ver- 
  

   rucac. 
  Externally 
  the 
  stomach 
  has 
  the 
  longitudinal 
  zonation 
  charac- 
  

   teristic 
  of 
  Thalassema 
  and 
  allies. 
  It 
  ends 
  abruptly 
  at 
  the 
  beginning 
  

   of 
  the 
  much 
  wider 
  midgut 
  with 
  its 
  ciliated 
  groove. 
  About 
  3 
  mm. 
  from 
  

   end 
  of 
  stomach 
  the 
  siphon 
  begins, 
  while 
  the 
  ciliated 
  groove 
  continues 
  

   adjacent 
  to 
  it, 
  along 
  the 
  inside 
  of 
  intestine 
  (pi. 
  35, 
  fig. 
  5). 
  A 
  strong 
  

   muscular 
  mesentery 
  subtends 
  the 
  stomach 
  and 
  is 
  attached 
  posteriorly 
  

   a 
  little 
  to 
  left 
  of 
  nerve 
  cord 
  {^P). 
  In 
  chilcnsis 
  the 
  siphon 
  begins 
  9 
  mm. 
  

   from 
  end 
  of 
  stomach 
  as 
  compared 
  to 
  2.5-3 
  mm. 
  in 
  caupo. 
  

  

  The 
  course 
  of 
  the 
  intestine 
  in 
  a 
  fully 
  expanded 
  specimen 
  is 
  shown 
  

   in 
  plate 
  35, 
  figure 
  1. 
  The 
  anterior 
  and 
  posterior 
  portions 
  of 
  the 
  body 
  

   are 
  omitted. 
  Plate 
  36, 
  figure 
  4, 
  shows 
  the 
  cloacal 
  region 
  of 
  the 
  same 
  

   specimen. 
  It 
  will 
  be 
  seen 
  that 
  the 
  siphonal 
  part 
  of 
  the 
  intestine 
  is 
  

   very 
  long 
  and 
  includes 
  two 
  anterior 
  and 
  two 
  posterior 
  bends. 
  Three 
  

   segments 
  of 
  the 
  gut 
  are 
  attached 
  by 
  muscular 
  mesenteries 
  on 
  the 
  right 
  

   side 
  of 
  body 
  and 
  three 
  (including 
  the 
  big 
  "hind-gut") 
  are 
  attached 
  

   on 
  the 
  left 
  side. 
  The 
  foregut 
  is 
  not 
  attached 
  to 
  body 
  wall 
  except 
  by 
  

   the 
  strong 
  phamygeal 
  mesenteries 
  and 
  the 
  mesentery 
  of 
  the 
  stomach 
  

   (-IP). 
  In 
  this 
  figure 
  the 
  breadth 
  is 
  accentuated 
  because 
  the 
  body 
  

   wall 
  is 
  pinned 
  out 
  flat. 
  The 
  mesenteries 
  of 
  siphonal 
  gut 
  farthest 
  to 
  

   right 
  are 
  attached 
  about 
  halfway 
  between 
  midventral 
  and 
  middorsal 
  

   lines. 
  

  

  The 
  postsiphonal 
  "small 
  intestine" 
  is 
  rather 
  short 
  and 
  is 
  anchored 
  

   by 
  heavier 
  mesenteries 
  than 
  are 
  found 
  on 
  the 
  siphonal 
  portion 
  anterior 
  

   to 
  the 
  last 
  loop. 
  The 
  "hind-gut," 
  used 
  as 
  a 
  respiratory 
  organ, 
  varies 
  

   in 
  dilation 
  and 
  consequent 
  thickness 
  of 
  wall 
  in 
  difrerent 
  specimens. 
  

   The 
  wall 
  is 
  usually 
  thin 
  and 
  translucent. 
  It 
  is 
  firmly 
  anchored 
  along 
  

   its 
  entire 
  length 
  on 
  the 
  left 
  side 
  of 
  the 
  nerve 
  cord. 
  On 
  plate 
  36, 
  

   figures 
  1-3, 
  I 
  have 
  shown 
  the 
  attachment 
  of 
  the 
  anterior 
  end 
  of 
  the 
  

   "hind-gut" 
  in 
  the 
  three 
  species. 
  Unless 
  the 
  single 
  specimen 
  of 
  

   cliilensis 
  available 
  for 
  dissection 
  is 
  abnormal, 
  there 
  is 
  considerable 
  

   difference 
  between 
  it 
  and 
  caupo. 
  

  

  The 
  cloaca 
  is 
  probably 
  normally 
  elongate 
  as 
  shown 
  in 
  plate 
  36, 
  

   figure 
  4. 
  It 
  is 
  here 
  shown 
  opened 
  for 
  the 
  entire 
  lengtli. 
  'J'he 
  mucosa 
  

   of 
  the 
  posterior 
  third 
  is 
  deeply 
  furrowed 
  longitudinMlly, 
  and 
  in 
  this 
  

   part, 
  on 
  the 
  ventral 
  side, 
  are 
  the 
  openings 
  of 
  the 
  two 
  anal 
  vesicles. 
  

   The 
  fecal 
  pellets 
  which 
  sometimes 
  crowd 
  the 
  i)ortion 
  of 
  small 
  intestine 
  

   shown 
  in 
  plate 
  34, 
  figure 
  1, 
  are 
  cylindrical 
  with 
  rounded 
  ends 
  (pi. 
  35, 
  

   fig. 
  (V). 
  

  

  T\\v 
  fresh 
  colors 
  of 
  the 
  viscera 
  in 
  an 
  anesthcti/cd 
  specimen 
  are: 
  

   Foregut, 
  pale 
  flesh 
  or 
  skin 
  color; 
  anterior 
  third 
  of 
  midgut 
  i)ale 
  gray- 
  

   green 
  mottled 
  Nsith 
  brown; 
  middle 
  third, 
  mottled 
  yellow 
  antl 
  dull 
  

  

  