﻿18 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL, 
  MUSEUM 
  vol. 
  67 
  

  

  neck 
  forming 
  the 
  round 
  part, 
  which 
  proved 
  to 
  be 
  unexpectedly 
  long, 
  

   and 
  after 
  executing 
  a 
  doubly 
  reversed 
  curve 
  passed 
  out 
  of 
  the 
  coil 
  

   and 
  finally 
  terminated 
  at 
  the 
  crown, 
  which 
  thus 
  assumed 
  an 
  erect 
  

   position. 
  It 
  is 
  small 
  and 
  fragile, 
  and 
  while 
  the 
  arms 
  are 
  preserved 
  

   to 
  nearly 
  their 
  full 
  length 
  the 
  structure 
  of 
  the 
  calyx 
  can 
  not 
  be 
  fully 
  

   made 
  out, 
  so 
  that 
  beyond 
  its 
  locrinus-like 
  appearance 
  not 
  much 
  

   can 
  be 
  said 
  about 
  it. 
  Encouraged 
  by 
  this 
  favorable 
  beginning 
  in 
  

   the 
  new 
  material, 
  expectation 
  was 
  aroused 
  that 
  we 
  should 
  soon 
  

   have 
  the 
  desired 
  information 
  as 
  to 
  its 
  exact 
  structure. 
  The 
  second 
  

   specimen 
  investigated 
  followed 
  the 
  same 
  course 
  as 
  the 
  first 
  until 
  the 
  

   slender 
  neck 
  of 
  the 
  stem 
  turned 
  outward 
  from 
  the 
  coil, 
  and 
  then 
  it 
  

   suddenly 
  came 
  to 
  an 
  end, 
  broken 
  squarely 
  off, 
  with 
  the 
  crown 
  absent 
  

   And 
  although 
  I 
  worked 
  every 
  specimen, 
  thirty-four 
  in 
  number, 
  in 
  

   which 
  the 
  favorable 
  condition 
  appeared, 
  the 
  same 
  result 
  followed. 
  

   In 
  every 
  one 
  of 
  them 
  the 
  crown 
  was 
  gone 
  — 
  snapped 
  off 
  at 
  time 
  of 
  

   death. 
  This 
  form 
  must 
  have 
  been 
  peculiarly 
  sensitive 
  to 
  disturbance 
  

   or 
  change 
  of 
  conditions, 
  causing 
  it 
  to 
  cast 
  off 
  the 
  crown, 
  as 
  certain 
  

   existing 
  crinoids 
  cast 
  off 
  their 
  arms 
  on 
  being 
  brought 
  to 
  the 
  surface. 
  

  

  Conformably 
  to 
  the 
  habitus 
  thus 
  described, 
  I 
  do 
  not 
  find 
  in 
  this 
  

   species 
  the 
  close 
  coiling 
  of 
  the 
  stem 
  in 
  the 
  proximal 
  region 
  as 
  in 
  the 
  

   other 
  species. 
  The 
  contrast 
  in 
  thickness 
  between 
  this 
  part 
  of 
  the 
  

   stem 
  and 
  that 
  lower 
  down 
  is 
  very 
  great. 
  The 
  broad 
  curve 
  in 
  the 
  

   latter 
  part 
  is 
  always 
  conspicuous, 
  terminating 
  when 
  sufficiently 
  pre- 
  

   served 
  to 
  show 
  it 
  in 
  a 
  pointed 
  end. 
  

  

  In 
  a 
  maximum 
  specimen 
  the 
  diameter 
  of 
  the 
  coil 
  is 
  15 
  mm. 
  ; 
  length 
  

   of 
  stem 
  from 
  coil 
  to 
  distal 
  end 
  is 
  30 
  mm. 
  ; 
  and 
  of 
  the 
  part 
  included 
  

   in 
  the 
  coil 
  about 
  35 
  mm., 
  to 
  which 
  must 
  be 
  added 
  that 
  of 
  the 
  circular 
  

   part, 
  20 
  mm., 
  making 
  the 
  total 
  length 
  of 
  stem 
  10 
  cm. 
  Width 
  of 
  stem 
  

   in 
  middle 
  region 
  4 
  mm., 
  in 
  circular 
  proximal 
  part 
  1 
  mm. 
  Length 
  

   of 
  an 
  upper 
  cirrus, 
  branching 
  four 
  times, 
  2.5 
  cm.; 
  lower 
  cirri, 
  not 
  

   fully 
  preserved, 
  undoubtedly 
  much 
  longer. 
  Maximum 
  number 
  of 
  

   cirri 
  about 
  12 
  or 
  13, 
  at 
  intervals 
  of 
  about 
  6 
  or 
  7 
  columnals 
  between 
  

   the 
  cirri 
  at 
  each 
  side. 
  The 
  columnals 
  are 
  quadrangular, 
  very 
  short, 
  

   and 
  of 
  uniform 
  length, 
  about 
  .5 
  to 
  .8 
  mm. 
  The 
  diameter 
  of 
  an 
  

   average 
  cirrus 
  at 
  its 
  base 
  is 
  1.5 
  mm., 
  so 
  that 
  its 
  socket 
  may 
  abut 
  

   upon 
  2 
  or 
  3 
  columnals. 
  Minimum 
  specimens 
  may 
  have 
  a 
  diameter 
  

   of 
  coil 
  of 
  7 
  mm. 
  or 
  less, 
  with 
  other 
  dimensions 
  in 
  proportion. 
  

  

  This 
  species 
  is 
  comparable 
  to 
  Ilerpetocrinus 
  flabellicirrus 
  Bather, 
  

   from 
  Gotland, 
  in 
  the 
  fact 
  that 
  the 
  cirri 
  spring 
  from 
  the 
  back 
  of 
  the 
  

   stem 
  and 
  are 
  confined 
  to 
  the 
  distal 
  region, 
  but 
  in 
  no 
  other 
  important 
  

   character. 
  In 
  the 
  Gotland 
  species, 
  instead 
  of 
  single 
  cirri 
  at 
  in- 
  

   tervals, 
  there 
  are 
  large 
  cirri 
  separated 
  by 
  several 
  columnals 
  bearing 
  

   successive 
  \y 
  diminishing 
  cirri, 
  arranged 
  so 
  as 
  to 
  form 
  a 
  fan-like 
  

   cluster. 
  Compare 
  Bather's 
  figure 
  68 
  of 
  plate 
  2, 
  with 
  figure 
  5 
  of 
  plate 
  

   4 
  herein. 
  

  

  