﻿smith: 
  on 
  the 
  young 
  stage 
  of 
  iiumphbei'ia. 
  25 
  

  

  and 
  transverse, 
  and 
  at 
  this 
  part 
  the 
  siliceous 
  grains 
  were 
  very 
  

   numerous. 
  

  

  The 
  anterior 
  slit 
  may 
  correspond 
  to 
  the 
  pedal 
  opening 
  which 
  is 
  

   present 
  in 
  the 
  animal 
  of 
  Brechites, 
  and 
  the 
  posterior 
  to 
  the 
  siphonal 
  

   end 
  of 
  that 
  genus. 
  What 
  may 
  be 
  the 
  function 
  of 
  the 
  flagelliform 
  

   extension 
  of 
  the 
  body 
  I 
  cannot 
  offer 
  an 
  opinion 
  upon. 
  Can 
  it 
  possibly 
  

   be 
  an 
  anchoring 
  appendage 
  ? 
  The 
  adductor 
  muscles 
  are 
  distinctly 
  

   visible 
  at 
  the 
  dorsal 
  end 
  of 
  the 
  body. 
  On 
  slitting 
  the 
  mantle 
  the 
  gills 
  

   were 
  seen 
  to 
  be 
  very 
  large, 
  whereas 
  both 
  the 
  foot 
  and 
  papi 
  were 
  

   minute. 
  Length 
  of 
  swollen 
  portion 
  of 
  the 
  body 
  about 
  lOmra., 
  of 
  the 
  

   prolongation 
  about 
  15 
  mm. 
  

  

  From 
  the 
  above 
  description, 
  brief 
  as 
  it 
  is, 
  it 
  will 
  be 
  seen 
  that 
  the 
  

   general 
  features 
  of 
  this 
  genus 
  practically 
  correspond 
  to 
  those 
  of 
  

   BrecMtes 
  as 
  described 
  by 
  Lacaze-Duthiers.' 
  

  

  It 
  is 
  a 
  matter 
  of 
  speculation 
  at 
  what 
  period 
  the 
  animal 
  commences 
  

   to 
  form 
  the 
  tube, 
  but 
  it 
  seems 
  probable 
  that 
  it 
  would 
  increase 
  con- 
  

   siderably 
  before 
  this 
  takes 
  place. 
  

  

  A 
  fanciful 
  account 
  of 
  the 
  development 
  of 
  Brechites 
  was 
  given 
  by 
  

   Dr. 
  J. 
  E. 
  Gray 
  in 
  the 
  Ann. 
  Mag. 
  Nat. 
  Hist., 
  1858, 
  vol. 
  i, 
  pp. 
  423-6. 
  

  

  ' 
  Arch. 
  Zool. 
  Expcrim., 
  ser. 
  ii, 
  vol. 
  i, 
  pp. 
  665-732, 
  pis. 
  xxv-ix. 
  

  

  