﻿SipJionophora 
  of 
  the 
  Canary 
  Island*. 
  223 
  

  

  at 
  the 
  broader 
  pole 
  a 
  comparatively 
  small 
  subumbrella 
  with 
  

   the 
  velum, 
  the 
  four 
  vessels, 
  and 
  the 
  annular 
  canal. 
  The 
  

   connecting 
  vascular 
  canal, 
  as 
  also 
  the 
  elongated 
  and 
  very 
  

   fine 
  fluid-receptacle 
  (s) 
  takes 
  a 
  nearly 
  horizontal 
  course. 
  The 
  

   comparatively 
  large 
  sheath 
  (v) 
  reaches 
  exactly 
  to 
  the 
  fluid- 
  

   receptacle 
  and 
  extends 
  to 
  the 
  inferior 
  margin 
  of 
  the 
  subum- 
  

   brella. 
  The 
  young 
  colony 
  is 
  now 
  seated 
  with 
  a 
  broad 
  base 
  

   upon 
  the 
  fluid-receptacle 
  of 
  the 
  primary 
  calyx. 
  As 
  regards 
  

   the 
  first-formed 
  definitive 
  Hippopodius-calyx 
  (B) 
  it 
  shows 
  

   perfectly 
  the 
  characteristic 
  horse-hoof 
  form. 
  As 
  its 
  peculiar 
  

   form 
  has 
  been 
  sufficiently 
  described 
  by 
  previous 
  observers, 
  I 
  

   mention 
  only 
  that 
  the 
  upper 
  radial 
  vessel 
  traversing 
  the 
  middle 
  

   of 
  the 
  subumbrella 
  already 
  shows 
  thecharacteristic 
  lateral 
  rami- 
  

   fications 
  which 
  lead 
  to 
  the 
  formation 
  of 
  the 
  vascular 
  plate 
  with 
  

   its 
  numerous 
  anastomoses. 
  The 
  fluid-receptacle 
  (s') 
  runs 
  out 
  

   into 
  the 
  section 
  of 
  the 
  stem 
  on 
  which 
  thecalyces 
  bud 
  between 
  the 
  

   lateral 
  wings 
  (Fl) 
  of 
  the 
  secondary 
  calyx. 
  The 
  rudiment 
  of 
  a 
  

   second 
  secondary 
  calyx 
  (B 
  ! 
  ) 
  in 
  the 
  form 
  of 
  a 
  rounded 
  bud, 
  at 
  

   the 
  base 
  of 
  which 
  a 
  small 
  thickening 
  already 
  indicates 
  the 
  

   formation 
  of 
  a 
  third 
  calyx, 
  is 
  distinctly 
  recognizable. 
  The 
  

   cushion-like 
  thickening 
  of 
  the 
  stem 
  by 
  which 
  the 
  attachment 
  

   to 
  the 
  primary 
  calyx 
  is 
  effected 
  consists 
  of 
  endodermic 
  cells 
  

   rich 
  in 
  fluid, 
  upon 
  which 
  lies 
  an 
  ectodermal 
  muscular 
  layer 
  

   {mu) 
  projecting 
  in 
  the 
  form 
  of 
  a 
  lamella. 
  By 
  the 
  contrac- 
  

   tion 
  of 
  the 
  latter 
  the 
  secondary 
  calyx 
  is 
  drawn 
  into 
  the 
  supe- 
  

   rior 
  section 
  of 
  the 
  sheath 
  on 
  the 
  slightest 
  contact. 
  If 
  the 
  

   two 
  calyces 
  separate 
  from 
  each 
  other 
  the 
  above-mentioned 
  

   cushion, 
  with 
  the 
  muscular 
  layer, 
  begins 
  to 
  shrivel 
  up 
  ; 
  but 
  

   it 
  may 
  still 
  be 
  recognized 
  for 
  a 
  long 
  time 
  in 
  young 
  colonies. 
  

  

  In 
  the 
  further 
  progress 
  we 
  come 
  first 
  upon 
  the 
  youngest 
  

   group 
  of 
  polyps, 
  consisting 
  of 
  a 
  young 
  stomachal 
  tube 
  (poly- 
  

   pite, 
  Huxl.) 
  and 
  a 
  tentacular 
  bud. 
  Two 
  further 
  developed 
  

   groups, 
  of 
  which 
  the 
  tentacles 
  already 
  show 
  the 
  characteristic 
  

   urticating 
  batteries 
  with 
  their 
  yellow 
  pigment, 
  hang 
  out 
  of 
  

   the 
  sheath 
  upon 
  the 
  elongated 
  stem. 
  

  

  I 
  content 
  myself 
  here 
  with 
  the 
  description 
  of 
  this 
  charac- 
  

   teristic 
  stage, 
  as 
  I 
  shall 
  shortly 
  give 
  elsewhere 
  a 
  full 
  descrip- 
  

   tion 
  of 
  the 
  postembryonic 
  development 
  of 
  Hippopodius. 
  

  

  Jn 
  giving 
  now 
  brief 
  characters 
  of 
  the 
  Canarian 
  Siphono- 
  

   phora, 
  at 
  the 
  same 
  time 
  inserting 
  occasional 
  remarks 
  upon 
  

   their 
  young 
  stages, 
  I 
  may 
  remark 
  that 
  I 
  cannot 
  approve 
  of 
  

   lliickel 
  having 
  so 
  extensively 
  replaced 
  the 
  older 
  and 
  often 
  

   lung-established 
  denominations 
  of 
  the 
  orders 
  and 
  families 
  by 
  

   new 
  ones, 
  which 
  are 
  frequently 
  but 
  little 
  altered 
  and 
  scarcely 
  

   more 
  applicable 
  (as, 
  for 
  example, 
  Calycophoridae 
  and 
  Pneu- 
  

   matophoridai 
  by 
  Calyconectse 
  and 
  Cystonectae). 
  

  

  16* 
  

  

  