﻿288 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  se 
  

  

  5, 
  Anterior 
  end 
  of 
  an 
  individual, 
  the 
  short 
  proboscis 
  apparently 
  in 
  process 
  of 
  

  

  regeneration, 
  X 
  3. 
  

  

  6, 
  Ventral 
  view 
  of 
  a 
  worm 
  life 
  size; 
  the 
  second 
  proboscis 
  indicates 
  about 
  the 
  

  

  maximum 
  length 
  in 
  preserved 
  specimens. 
  

  

  7, 
  Anterior 
  ventral 
  portion 
  of 
  worm 
  showing 
  the 
  contracted 
  verrucose 
  skin, 
  X 
  10; 
  

  

  when 
  the 
  skin 
  is 
  fully 
  distended 
  the 
  verrucae 
  disappear, 
  the 
  glandular 
  thick- 
  

   enings 
  then 
  appearing 
  as 
  squarish 
  patches, 
  closely 
  spaced. 
  

   Go, 
  gonad; 
  other 
  lettering 
  as 
  for 
  plate 
  24. 
  

  

  Plate 
  27 
  

  

  Bonelliopsis 
  alaskana, 
  new 
  genus 
  and 
  species 
  

  

  1, 
  Dissection 
  of 
  anterior 
  end 
  of 
  a 
  specimen 
  with 
  a 
  right 
  nephridium 
  filled 
  with 
  

  

  eggs, 
  X 
  5. 
  A 
  "window" 
  has 
  been 
  cut 
  in 
  the 
  dorsal 
  wall 
  of 
  pharynx 
  and 
  also 
  

   one 
  in 
  the 
  nephridium 
  to 
  show 
  the 
  invaginated 
  tip, 
  within 
  which 
  is 
  the 
  

   nephrostome. 
  The 
  longitudinal 
  ridges 
  on 
  inner 
  wall 
  of 
  nephridium 
  are 
  indi- 
  

   cated 
  by 
  dotted 
  lines. 
  

  

  2, 
  Same, 
  anterior 
  end, 
  in 
  contracted 
  state, 
  with 
  right 
  half 
  removed 
  to 
  show 
  

  

  relation 
  of 
  dorsal 
  and 
  ventral 
  mesenteries 
  to 
  alimentary 
  canal 
  and 
  ventral 
  

   mesenteries 
  to 
  alimentary 
  canal 
  and 
  nephridium, 
  X 
  5. 
  Anteriorly 
  only 
  a 
  

   few 
  of 
  the 
  frenula 
  of 
  pharynx 
  indicated; 
  back 
  of 
  these 
  the 
  transverse 
  mesen- 
  

   tery 
  of 
  figure 
  1 
  (M' 
  ) 
  is 
  indicated 
  as 
  a 
  black 
  line. 
  DM, 
  dorsal 
  mesentery, 
  and 
  

   DM^ 
  (dot-dash), 
  its 
  attachment 
  to 
  right 
  wall 
  of 
  body 
  (removed); 
  VM, 
  

   ventral 
  mesentery, 
  attached 
  to 
  lower 
  side 
  of 
  intestine 
  and 
  mostly 
  to 
  left 
  side 
  

   of 
  f 
  oregut 
  and 
  involving 
  posterior 
  part 
  of 
  dorsal 
  artery 
  (B') 
  . 
  The 
  nephridium 
  

   lies 
  in 
  a 
  sort 
  of 
  anterior 
  cul-de-sac 
  or 
  egg 
  trap. 
  When 
  the 
  animal 
  is 
  extended 
  

   the 
  upper 
  margin 
  of 
  dorsal 
  mesentery 
  is 
  at 
  a 
  distance 
  behind 
  the 
  nephridium, 
  

   here 
  shown 
  at 
  minimum 
  size. 
  

  

  Af' 
  , 
  a 
  transverse 
  mesentery 
  below 
  the 
  dorsal 
  blood 
  vessel; 
  

  

  M', 
  special 
  muscular 
  mesentery 
  between 
  gizzard 
  and 
  stomach, 
  not 
  shown 
  in 
  figure 
  

   2; 
  PV, 
  position 
  of 
  pyloric 
  valve, 
  mentioned 
  in 
  text; 
  other 
  lettering 
  as 
  for 
  

   plate 
  24. 
  

  

  Plate 
  28 
  

  

  Eubonellia 
  valida, 
  new 
  genus 
  and 
  species 
  

  

  1, 
  Dissection 
  of 
  anterior 
  end 
  of 
  body 
  from 
  above, 
  X 
  4. 
  The 
  f 
  oregut 
  has 
  been 
  

  

  drawn 
  to 
  the 
  left 
  to 
  show 
  the 
  large 
  nephridium 
  (N) 
  with 
  its 
  terminal 
  nephro- 
  

   stome 
  (CF). 
  Note 
  the 
  unusually 
  long 
  stomach 
  (C), 
  filled 
  with 
  pellets, 
  

   between 
  the 
  gizzard 
  (G) 
  and 
  intestine 
  (/). 
  The 
  ventral 
  blood 
  vessel 
  (B*) 
  

   and 
  the 
  much 
  contracted 
  neurointestinal 
  vessel 
  (B') 
  have 
  been 
  cross- 
  

   hatched. 
  The 
  dorsal 
  blood 
  vessel 
  (B') 
  is 
  unshaded. 
  

  

  2, 
  A 
  cluster 
  of 
  nephric 
  elements 
  of 
  an 
  anal 
  vesicle, 
  X 
  30. 
  

  

  3, 
  Type, 
  natural 
  size, 
  from 
  below. 
  

  

  4, 
  A 
  pellet 
  from 
  the 
  postsiphonal 
  intestine, 
  X 
  10. 
  

  

  5, 
  Male, 
  from 
  mouth 
  cavity, 
  X 
  50; 
  anterior 
  end 
  to 
  right; 
  the 
  sperm 
  receptacle 
  and 
  

  

  duct 
  shown. 
  

   Lettering 
  as 
  for 
  plate 
  24. 
  

  

  Plate 
  29 
  

  

  Nellobia 
  eusoma, 
  new 
  genus 
  and 
  species 
  

  

  1, 
  Ventral 
  view 
  of 
  anterior 
  end 
  of 
  type 
  showing 
  the 
  short 
  truncate^snout, 
  X 
  5. 
  

  

  2, 
  Ventral 
  view 
  of 
  type, 
  X 
  1. 
  

  

  