﻿ECHINODEKMATA. 
  157 
  

  

  4. 
  Antedon 
  carpenter!. 
  (Plate 
  X. 
  figs. 
  A, 
  a-c.) 
  

  

  Centrodorsal 
  a 
  flattened 
  disk 
  ; 
  about 
  12 
  marginal 
  cirri, 
  of 
  almost 
  

   20 
  short 
  joints, 
  of 
  which 
  tlie 
  lowest 
  are 
  almost 
  twice 
  as 
  broad 
  as 
  

   they 
  are 
  long 
  ; 
  it 
  is 
  not 
  till 
  we 
  reach 
  the 
  penultimate 
  one 
  that 
  we 
  

   see 
  a 
  distinct 
  spine, 
  though 
  the 
  dorsal 
  surface 
  of 
  most 
  of 
  them 
  is 
  

   produced 
  into 
  a 
  minute 
  protuberance. 
  

  

  First 
  radials 
  not 
  visible 
  ; 
  the 
  second 
  do 
  not 
  or 
  do 
  only 
  slightly 
  

   touch, 
  united 
  to 
  the 
  third 
  by 
  ligament. 
  Ten 
  arms. 
  First 
  brachials 
  

   touch, 
  they 
  are 
  nearly 
  oblong 
  and 
  more 
  than 
  twice 
  as 
  wide 
  as 
  long 
  ; 
  

   the 
  second 
  are 
  a 
  little 
  wider 
  on 
  their 
  outer 
  than 
  their 
  inner 
  side 
  ; 
  

   the 
  third 
  with 
  a 
  syzygy 
  ; 
  fourth 
  to 
  sixth 
  oblong, 
  seventh 
  wider 
  on 
  

   inner 
  than 
  outer 
  side, 
  eighth 
  wider 
  on 
  their 
  outer 
  than 
  inner, 
  and 
  

   so 
  on 
  alternately 
  ; 
  twelfth 
  and 
  thirteenth 
  serrated 
  at 
  their 
  distal 
  

   edge 
  ; 
  the 
  fourteenth 
  syzygial. 
  Thence 
  from 
  four 
  to 
  seven 
  joints 
  

   between 
  each 
  syzygy. 
  130-180 
  joints 
  in 
  the 
  arm. 
  

  

  The 
  second 
  pinnules 
  on 
  the 
  fourth 
  brachial 
  are 
  very 
  stout, 
  with 
  

   extraordinarily 
  wide 
  joints, 
  which 
  are 
  armed 
  on 
  either 
  side 
  by 
  

   spinous 
  projections 
  ; 
  the 
  first 
  pinnule 
  is 
  a 
  little 
  longer 
  than 
  the 
  

   third. 
  

  

  Colour 
  white, 
  with 
  purple 
  bands 
  or 
  patches, 
  not 
  always 
  developed 
  

   at 
  the 
  syzygies. 
  The 
  middle 
  line 
  of 
  the 
  arm 
  often 
  white. 
  

  

  Arm 
  about 
  40 
  millim. 
  long, 
  disk 
  6 
  millim. 
  in 
  diameter, 
  cirri 
  less 
  

   than 
  9 
  millim. 
  long. 
  

  

  This 
  species 
  has 
  some 
  considerable 
  resemblances 
  to 
  A. 
  serripimia, 
  

   from 
  which, 
  however, 
  the 
  pinnules 
  alone 
  would, 
  as 
  Mr. 
  Carpenter 
  

   assures 
  me, 
  be 
  sufiicient 
  to 
  distinguish 
  it. 
  

  

  Port 
  Curtis. 
  

  

  5. 
  Antedon 
  pumila. 
  (Plate 
  X. 
  figs. 
  B, 
  a-h.) 
  

  

  Centrodorsal 
  rather 
  wide, 
  rounded 
  ; 
  with 
  about 
  25 
  cirri, 
  in 
  three 
  

   rows, 
  very 
  delicate, 
  of 
  about 
  12 
  joints, 
  which, 
  from 
  the 
  fourth 
  onward, 
  

   are 
  a 
  good 
  deal 
  longer 
  than 
  broad, 
  hourglass-shaped, 
  but 
  a 
  little 
  wider 
  

   at 
  their 
  distal 
  than 
  at 
  their 
  proximal 
  ends 
  ; 
  some 
  are 
  also 
  produced 
  

   into 
  a 
  small 
  spinous 
  ventral 
  process 
  ; 
  no 
  dorsal 
  spine 
  developed 
  till 
  

   the 
  penultimate, 
  and 
  that 
  is 
  small. 
  

  

  First 
  radials 
  just 
  visible, 
  second 
  not 
  in 
  contact 
  ; 
  axillaries 
  tri- 
  

   angular 
  in 
  shape, 
  sloping 
  backwards 
  in 
  the 
  middle 
  line. 
  Ten 
  arms. 
  

   First 
  brachial 
  longer 
  without 
  than 
  within, 
  the 
  second 
  within 
  than 
  

   without 
  and 
  projecting 
  backwards 
  in 
  the 
  middle 
  line 
  ; 
  the 
  third 
  

   a 
  syzygy 
  wider 
  within 
  than 
  without. 
  The 
  succeeding 
  joints 
  

   may 
  be 
  incised, 
  so 
  as 
  to 
  leave 
  a 
  lozenge-shaped 
  space 
  between 
  

   every 
  two 
  ; 
  when 
  this 
  disappears, 
  the 
  joints 
  which 
  have 
  projected 
  

   strongly 
  forwards 
  on 
  either 
  side 
  alternately 
  become 
  more 
  evenly 
  

   oblong. 
  

  

  Syzygies 
  3, 
  <S, 
  12, 
  15 
  ; 
  then 
  a 
  little 
  rarer. 
  

  

  Pinnules 
  delicate, 
  the 
  second 
  longer 
  than 
  the 
  first, 
  with 
  elongated 
  

   joints 
  which 
  are 
  a 
  little 
  wider 
  at 
  their 
  distal 
  than 
  at 
  their 
  proximal 
  

   end 
  and 
  are 
  produced 
  into 
  a 
  minute 
  spiue. 
  

  

  