﻿254 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol.96 
  

  

  tery 
  on 
  its 
  left 
  side, 
  where 
  the 
  foregut 
  enters 
  the 
  intestine. 
  In 
  the 
  

   drawing 
  the 
  posterior 
  face 
  of 
  dorsal 
  mesentery 
  is 
  shown 
  and 
  only 
  a 
  

   small 
  part 
  of 
  the 
  anterior 
  (or 
  dorsal) 
  side 
  adjacent 
  to 
  pharynx. 
  The 
  

   attachment 
  to 
  the 
  gut 
  is 
  along 
  the 
  lateral 
  line, 
  but 
  behind 
  gizzard 
  the 
  

   attachment 
  moves 
  over 
  near 
  to 
  that 
  of 
  ventral 
  mesentery. 
  A 
  special 
  

   muscular 
  mesentery 
  indicated 
  in 
  plate 
  27, 
  figure 
  1, 
  but 
  omitted 
  from 
  

   figure 
  2, 
  joins 
  the 
  gizzard 
  to 
  the 
  stomach. 
  A 
  special 
  transverse 
  dorsal 
  

   muscular 
  mesentery 
  supports 
  the 
  dorsal 
  blood 
  vessel 
  anteriorly. 
  

   When 
  the 
  animal 
  is 
  extended 
  the 
  effect 
  of 
  these 
  mesenteries 
  is 
  to 
  form 
  

   a 
  somewhat 
  spiral 
  anterior 
  cul-de-sac 
  in 
  which 
  the 
  nephridium 
  lies 
  

   and 
  in 
  which 
  the 
  eggs 
  probably 
  congregate. 
  But 
  when 
  the 
  neplnidium 
  

   is 
  full 
  of 
  eggs, 
  as 
  in 
  plate 
  27, 
  figure 
  1, 
  there 
  may 
  still 
  be 
  hundreds 
  of 
  

   eggs, 
  seemingly 
  mature, 
  in 
  various 
  parts 
  of 
  the 
  coelom. 
  

  

  Vascular 
  system. 
  The 
  distribution 
  of 
  the 
  principal 
  trunks, 
  

   shown 
  in 
  the 
  figures, 
  seems 
  to 
  be 
  almost 
  the 
  same 
  as 
  in 
  Bonellia 
  

   viridis 
  (fig. 
  15). 
  The 
  connection 
  between 
  the 
  dorsal 
  and 
  ventral 
  

   vessels 
  is 
  not 
  direct, 
  as 
  in 
  Echiurus, 
  Ochetostoma, 
  and 
  Thalassema, 
  

   but 
  by 
  means 
  of 
  lacunae 
  in 
  the 
  intestinal 
  wall, 
  as 
  is 
  the 
  case 
  in 
  

   Arhynchite. 
  

  

  The 
  gonad 
  lying 
  along 
  the 
  top 
  of 
  the 
  ventral 
  blood 
  vessel, 
  in 
  the 
  

   posterior 
  half 
  of 
  body, 
  seems 
  to 
  be 
  identical 
  with 
  that 
  of 
  B. 
  viridis. 
  

  

  Male. 
  The 
  males 
  are 
  fomid 
  in 
  the 
  foregut, 
  from 
  the 
  pharynx 
  to 
  

   the 
  gizzard, 
  in 
  the 
  order 
  of 
  about 
  a 
  dozen 
  to 
  an 
  individual. 
  In 
  one 
  

   case 
  I 
  found 
  two 
  or 
  three 
  in 
  the 
  anterior 
  part 
  of 
  the 
  stomach. 
  Dr. 
  H. 
  

   Heath, 
  who 
  collected 
  the 
  type 
  series, 
  examined 
  several 
  live 
  specimens 
  

   and 
  found 
  no 
  males 
  in 
  the 
  nephridium. 
  

  

  The 
  males 
  vary 
  from 
  elongate-slender 
  to 
  the 
  shortened 
  state 
  shown 
  

   in 
  figure 
  16. 
  When 
  fully 
  extended 
  they 
  are 
  more 
  than 
  twice 
  as 
  long 
  

   as 
  figure 
  and 
  only 
  about 
  half 
  as 
  thick. 
  The 
  sperm 
  receptacle 
  is 
  

   situated 
  posterior 
  to 
  middle 
  of 
  body 
  and 
  the 
  duct 
  opens 
  at 
  anterior 
  

   end, 
  or 
  very 
  close 
  to 
  it. 
  There 
  is 
  very 
  little 
  free 
  coelom, 
  the 
  body 
  

   being 
  filled 
  with 
  parenchymatous 
  and 
  muscle 
  tissue, 
  diagrammatically 
  

   indicated 
  by 
  the 
  more 
  spaced 
  dots 
  in 
  figure. 
  No 
  setae 
  are 
  present. 
  

  

  Type.— 
  U.S. 
  ^M. 
  No. 
  20603. 
  

  

  Type 
  locality. 
  — 
  Dutch 
  Harbor, 
  Unalaska, 
  under 
  rocks, 
  at 
  low 
  

   tide; 
  Harold 
  Heath, 
  August 
  1917, 
  15 
  specimens. 
  

  

  Specimens 
  examined. 
  — 
  In 
  addition 
  to 
  the 
  above, 
  25 
  specimens, 
  

   without 
  locality, 
  U. 
  S. 
  National 
  Museum. 
  

  

  Remarks. 
  — 
  The 
  type 
  series 
  was 
  collected 
  by 
  Dr. 
  Harold 
  Heath, 
  

   who 
  found 
  them 
  in 
  the 
  intertidal 
  zone 
  under 
  flat 
  rocks. 
  The 
  worms 
  

   were 
  arranged 
  around 
  the 
  periphery 
  of 
  the 
  stone 
  with 
  the 
  proboscis 
  

   extended 
  to 
  the 
  margin. 
  In 
  life 
  the 
  animals 
  are 
  light 
  green, 
  the 
  

   color 
  of 
  "green 
  prunes," 
  which, 
  in 
  the 
  contracted 
  state, 
  they 
  some- 
  

   what 
  resemble. 
  

  

  