﻿Report 
  U. 
  S, 
  F. 
  C, 
  1903 
  

  

  Plate 
  IX. 
  

  

  in 
  

  

  Fig. 
  1. 
  View 
  of 
  right 
  side 
  of 
  embryo 
  about 
  C 
  days 
  old. 
  wi, 
  mouth; 
  v, 
  vent; 
  I, 
  right 
  lobe 
  of 
  Hver; 
  vl, 
  velum. 
  

  

  Fig. 
  2. 
  Older 
  larva 
  of 
  European 
  oyster, 
  Ostrea 
  lurida. 
  L, 
  shell; 
  h, 
  hinge; 
  rs 
  and 
  ri, 
  retractor 
  muscles 
  of 
  

   the 
  velum, 
  vl; 
  s, 
  stomach; 
  t, 
  intestine; 
  am, 
  larval 
  adductor 
  muscle; 
  h, 
  body 
  cavity. 
  Other 
  letters 
  as 
  in 
  

   the 
  preceding. 
  

  

  Fig. 
  3. 
  Attached 
  spat 
  of 
  Ostrea 
  virginica. 
  S, 
  shell 
  of 
  spat 
  with 
  larval 
  shell, 
  L, 
  at 
  the 
  beak 
  or 
  umbo; 
  p, 
  

   palps; 
  g, 
  gills; 
  c, 
  diagrammatic 
  representation 
  of 
  a 
  single 
  row 
  of 
  cillia 
  extending 
  from 
  the 
  mantle 
  border 
  to 
  

   the 
  mouth 
  m; 
  ?% 
  radiating 
  muscle 
  fibres 
  of 
  mantle; 
  t, 
  rudimentary 
  tentacles 
  of 
  mantle 
  border; 
  M, 
  perma- 
  

   nent 
  adductor 
  muscle; 
  C, 
  cloaca; 
  ve 
  and 
  au, 
  ventricle 
  and 
  auricle 
  of 
  the 
  heart; 
  y, 
  posterior 
  extremity 
  of 
  

   the 
  gills 
  and 
  junction 
  of 
  the 
  mantle 
  folds. 
  Other 
  figures 
  as 
  above. 
  Compare 
  this 
  figure 
  with 
  PI. 
  I, 
  fig. 
  1. 
  

  

  Fig. 
  1 
  after 
  W. 
  K. 
  Brooks. 
  Fig. 
  2 
  after 
  Thomas 
  H. 
  Huxley. 
  Fig. 
  3 
  after 
  John 
  A. 
  Ryder. 
  

  

  