﻿NO. 
  1959. 
  SIFU\CULIDS 
  OF 
  EASTERN 
  NORTH 
  AMERICA— 
  GEROULD. 
  433 
  

  

  Sipunculus. 
  On 
  the 
  other 
  hand, 
  its 
  integument 
  and 
  muscles 
  are 
  

   more 
  Hke 
  those 
  of 
  Sipunculus, 
  though 
  as 
  pointed 
  out 
  to 
  me 
  by 
  Pro- 
  

   fessor 
  Spengel, 
  its 
  integumental 
  canals 
  are 
  isolated 
  blind 
  sacs 
  of 
  

   peculiar 
  form, 
  not 
  longitudinal 
  vessels 
  as 
  in 
  Sipunculus 
  nudus. 
  

  

  S. 
  cumanense 
  is 
  remarkable 
  for 
  the 
  presence 
  of 
  transverse 
  folds 
  of 
  

   peritoneum 
  that 
  cross 
  the 
  ccelom 
  at 
  regular 
  intervals 
  like 
  the 
  dissepi- 
  

   ments 
  of 
  an 
  annelid. 
  In 
  view 
  of 
  this 
  interesting 
  fact, 
  which 
  at 
  least 
  

   suggests 
  metameric 
  segmentation, 
  and 
  its 
  somewhat 
  generalized 
  

   structure 
  which 
  combmes 
  characteristic 
  features 
  of 
  two 
  genera, 
  a 
  

   knowledge 
  of 
  its 
  embryology 
  is 
  much 
  to 
  be 
  desired. 
  Its 
  spherical 
  

   eggs 
  are 
  exceedingly 
  transparent, 
  and 
  tliis 
  species 
  therefore 
  probably 
  

   would 
  be 
  very 
  favorable 
  for 
  observations 
  upon 
  the 
  living 
  embryo. 
  

   I 
  am 
  informed 
  by 
  Professor 
  Spengel 
  that 
  transverse 
  folds 
  of 
  perito- 
  

   neum 
  like 
  these 
  are 
  not 
  found 
  in 
  the 
  nearest 
  allies 
  of 
  this 
  species, 
  

   namely, 
  SipTionosoma 
  vastum, 
  arcassonense, 
  and 
  hoTiolense. 
  

  

  The 
  trunk 
  is 
  slender 
  and 
  cylindrical; 
  the 
  introvert 
  about 
  one-fifth 
  

   to 
  one-third 
  the 
  length 
  of 
  the 
  trunk. 
  The 
  largest 
  specimen 
  from 
  

   Oyster 
  Bay 
  measures: 
  Trunk 
  19 
  cm., 
  introvert 
  4.5 
  cm. 
  (well 
  ex- 
  

   panded). 
  The 
  specimens 
  are 
  of 
  grayish-brown 
  color, 
  and 
  the 
  body 
  

   wall 
  is 
  more 
  or 
  less 
  translucent, 
  the 
  typical 
  form 
  (those 
  from 
  Oyster 
  

   Bay) 
  being 
  Synapta-like 
  in 
  appearance, 
  whereas 
  those 
  from 
  Key 
  

   West 
  identified 
  as 
  the 
  variety 
  vitrea 
  have 
  a 
  more 
  gelatinous, 
  trans- 
  

   lucent 
  appearance. 
  A 
  narrow 
  zone 
  upon 
  the 
  base 
  of 
  the 
  introvert 
  

   is 
  of 
  a 
  lighter 
  gray, 
  and 
  is 
  covered 
  with 
  epidermal 
  organs 
  of 
  two 
  sizes, 
  

   the 
  larger 
  ones 
  being 
  placed 
  at 
  somewhat 
  regular 
  intervals, 
  with 
  the 
  

   smaller 
  irregularly 
  interspersed. 
  The 
  larger 
  have 
  the 
  form 
  of 
  flat 
  

   circular 
  or 
  elliptical 
  papiUse 
  with 
  a 
  pore 
  or 
  two 
  at 
  the 
  center. 
  The 
  

   core 
  of 
  the 
  smaller 
  organs 
  rises 
  slightly 
  above 
  the 
  general 
  surface 
  as 
  

   an 
  exceedingly 
  minute, 
  slender, 
  pointed 
  papilla. 
  The 
  latter 
  are 
  

   probably 
  sensory, 
  the 
  former 
  glandular 
  or 
  both 
  glandular 
  and 
  sen- 
  

   sory. 
  Epidermal 
  organs 
  are 
  also 
  visible 
  with 
  a 
  lens 
  at 
  the 
  posterior 
  

   extremity 
  of 
  the 
  body. 
  Elsewhere 
  they 
  are 
  extremely 
  mmute; 
  20-21 
  

   longitudinal 
  muscle 
  bands 
  are 
  distinctly 
  visible 
  through 
  the 
  body 
  waU, 
  

   the 
  surface 
  of 
  which 
  is 
  corrugated 
  with 
  furrows 
  corresponding 
  to 
  the 
  

   muscle 
  bands 
  and 
  with 
  intervening 
  parallel 
  ridges. 
  The 
  longitudinal 
  

   muscle 
  bands 
  run 
  to 
  the 
  extreme 
  posterior 
  end 
  of 
  the 
  body. 
  The 
  

   cuticula 
  of 
  the 
  introvert 
  upon 
  contraction 
  is 
  thrown 
  up 
  into 
  narrow 
  

   plate-like 
  folds, 
  but 
  no 
  hooks 
  are 
  present. 
  There 
  are 
  numerous 
  long, 
  

   slender 
  tentacles, 
  which 
  are 
  entirely 
  distinct 
  from 
  one 
  another 
  and 
  

   have 
  the 
  usual 
  longitudinal 
  groove 
  along 
  the 
  oral 
  surface. 
  The 
  

   nephridiopores 
  are 
  slightly 
  in 
  front 
  of 
  the 
  anus. 
  

  

  The 
  four 
  short 
  retractors 
  arise 
  from 
  the 
  body 
  wall 
  in 
  nearly 
  the 
  

   same 
  zone, 
  the 
  attachments 
  of 
  the 
  dorsal 
  in 
  some 
  specimens 
  being 
  

   very 
  slightly 
  in 
  front 
  of 
  those 
  of 
  the 
  ventral. 
  The 
  two 
  ventral 
  

   retractors 
  are 
  attached 
  to 
  the 
  second 
  and 
  third 
  longitudinal 
  muscle 
  

  

  69077"— 
  Proc.N.M.vol.44— 
  13 
  28 
  

  

  