﻿art. 
  5 
  THE 
  GENUS 
  PENTACPJNUS 
  — 
  SPRINGER 
  5 
  

  

  cm. 
  ; 
  the 
  increase 
  is 
  by 
  interpolation 
  of 
  new 
  internodals, 
  which 
  con- 
  

   tinues 
  progressively 
  further 
  down 
  along 
  the 
  stem, 
  the 
  interpolated 
  

   columnals 
  appearing 
  at 
  the 
  surface 
  in 
  the 
  form 
  of 
  short 
  and 
  thin 
  

   lacunae, 
  which 
  gradually 
  widen 
  and 
  coalesce 
  until 
  they 
  become 
  full 
  

   columnals, 
  and 
  these 
  increase 
  in 
  length 
  until 
  they 
  approach 
  the 
  size 
  

   of 
  those 
  adjoining 
  them. 
  So 
  the 
  next 
  increase 
  would 
  be 
  to 
  add 
  32 
  

   young 
  thin 
  ossicles 
  to 
  the 
  internode, 
  making 
  63 
  in 
  all 
  at 
  about 
  the 
  

   twenty-fourth 
  internode. 
  

  

  Thus 
  the 
  progression 
  would 
  be 
  about 
  like 
  this: 
  

  

  Internode 
  1 
  lias 
  1 
  long, 
  2 
  short 
  3 
  

  

  Internodes 
  2-5 
  have 
  1 
  long. 
  2 
  short, 
  4 
  lacunae 
  7 
  

  

  Internodes 
  6-10 
  have 
  3 
  long, 
  4 
  short, 
  8 
  lacunae 
  15 
  

  

  Internodes 
  11-17 
  have 
  7 
  long, 
  8 
  short, 
  16 
  lacunae 
  31 
  

  

  Internodes 
  18-25 
  have 
  15 
  long, 
  16 
  s-hort, 
  32 
  lacunae 
  63 
  

  

  Both 
  groups 
  are 
  cited 
  from 
  Wurtemburg, 
  but 
  apparently 
  only 
  P. 
  

   fossills 
  from 
  England. 
  De 
  Loriol 
  gives 
  a 
  list 
  of 
  the 
  species 
  in 
  the 
  

   two 
  groups, 
  and 
  declares 
  that 
  as 
  to 
  those 
  occurring 
  outside 
  of 
  France 
  

   they 
  have 
  not 
  been 
  described 
  with 
  sufficient 
  exactness 
  to 
  enable 
  him 
  to 
  

   recognize 
  them. 
  And 
  the 
  same 
  may 
  be 
  said 
  of 
  most 
  of 
  those 
  from 
  

   France. 
  In 
  fact 
  the 
  literature 
  is 
  encumbered 
  with 
  the 
  names 
  of 
  

   more 
  than 
  a 
  hundred 
  species 
  of 
  Pentacrinus^ 
  most 
  of 
  them 
  without 
  

   definition 
  by 
  which 
  they 
  can 
  be 
  recognized. 
  They 
  have 
  been 
  pro- 
  

   posed 
  chiefly 
  upon 
  isolated 
  stem-ossicles, 
  which 
  differ 
  much 
  in 
  con- 
  

   tour 
  and 
  markings 
  according 
  to 
  their 
  position 
  in 
  the 
  stem. 
  Outside 
  

   of 
  the 
  common 
  species 
  the 
  characters 
  are 
  not 
  well 
  known, 
  and 
  nothing 
  

   short 
  of 
  a 
  thorough 
  revision 
  of 
  all 
  species 
  based 
  upon 
  the 
  type 
  and 
  

   associated 
  material 
  will 
  afford 
  the 
  knowledge 
  necessary 
  for 
  com- 
  

   parison. 
  

  

  The 
  sj)ecimens 
  from 
  Alaska 
  without 
  doubt 
  belong 
  to 
  the 
  second, 
  

   or 
  subangularis, 
  group. 
  The 
  round 
  column, 
  and 
  strong 
  alternation 
  

   of 
  columnals 
  as 
  they 
  appear 
  in 
  figure 
  2 
  of 
  our 
  plate, 
  establish 
  this 
  

   conclusively. 
  Enough 
  is 
  visible 
  in 
  the 
  lateral 
  views 
  of 
  the 
  few 
  short 
  

   stem 
  fragments 
  exposed 
  to 
  show 
  that 
  the 
  internodal 
  columnals 
  merge 
  

   in 
  the 
  form 
  of 
  lacunae, 
  as 
  shown 
  by 
  figure 
  4, 
  and 
  as 
  further 
  ex- 
  

   plained 
  in 
  my 
  paper 
  on 
  Pentacrinus 
  rotiensis 
  from 
  the 
  East 
  Indies. 
  10 
  

  

  No 
  cirri 
  are 
  obseivable 
  on 
  the 
  parts 
  preserved. 
  The 
  sculpture 
  

   of 
  the 
  numerous 
  joint-faces 
  exposed 
  on 
  figure 
  2 
  is 
  precisely 
  of 
  the 
  

   type 
  of 
  the 
  Wurtemburg 
  specimens, 
  as 
  figured 
  in 
  the 
  above-men- 
  

   tioned 
  paper 
  (pi. 
  1, 
  figs. 
  3, 
  4, 
  and 
  herein, 
  fig. 
  3). 
  But 
  there 
  is 
  to 
  be 
  

   seen 
  a 
  slight 
  difference 
  in 
  the 
  outline 
  of 
  the 
  columnals, 
  that 
  of 
  the 
  

   latter 
  being 
  distinctly 
  subpentagonal, 
  while 
  those 
  of 
  our 
  specimens 
  

   are 
  almost' 
  uniformly 
  round, 
  a 
  difference 
  which 
  may 
  be 
  due 
  to 
  dif- 
  

   ferent 
  positions 
  in 
  the 
  stem. 
  

  

  10 
  Nederlandische 
  Tirnor-Expeditie 
  II. 
  Jaarboek 
  van 
  het 
  Mijnwesen, 
  4oe 
  Jaargang, 
  

   191G, 
  Leiden, 
  Holland. 
  Published 
  in 
  1918. 
  

  

  