﻿PLATE 
  XXXI. 
  

  

  COBtfULITES 
  PKOPRIUS 
  Hall, 
  

  

  Page 
  182. 
  

  

  Fig. 
  1. 
  A 
  group 
  of 
  young 
  individuals 
  attached 
  to 
  a 
  young 
  shell 
  of 
  Strophostylus 
  

  

  cyclostomus, 
  enlarged 
  to 
  two 
  diameters. 
  This 
  group 
  has 
  the 
  

  

  peculiarity 
  of 
  forming 
  an 
  irregular 
  circle— 
  the 
  only 
  instance 
  of 
  this 
  

   kind 
  observed. 
  

  

  Fig. 
  2. 
  A 
  large 
  specimen 
  attached 
  to 
  a 
  shell 
  of 
  the 
  same 
  species 
  as 
  above. 
  

  

  Fig. 
  3. 
  A 
  group 
  of 
  three 
  individuals 
  of 
  different 
  sizes 
  attached 
  to 
  the 
  shell 
  of 
  

   Platyostoma 
  Niagarense. 
  

  

  Fig. 
  4. 
  Lateral 
  view 
  of 
  a 
  large 
  specimen, 
  showing 
  the 
  usual 
  characters 
  of 
  the 
  

   fully 
  developed 
  form. 
  

  

  Fig. 
  5. 
  A 
  smaller 
  specimen 
  which 
  is 
  attached 
  to 
  the 
  side 
  of 
  the 
  cup 
  of 
  Eucalyp- 
  

   tocrinus 
  crassus. 
  The 
  attached 
  portion 
  of 
  the 
  tube 
  is 
  flattened 
  on 
  

   the 
  lower 
  side 
  and 
  thickened 
  above, 
  and 
  united 
  by 
  nearly 
  its 
  

   entire 
  width 
  to 
  the 
  crinoidal 
  plates. 
  

  

  Fig. 
  6. 
  A 
  specimen 
  of 
  very 
  irregular 
  growth 
  and 
  strongly 
  striated 
  surface. 
  

  

  Fig. 
  7. 
  Lateral 
  view 
  of 
  a 
  similar 
  specimen, 
  showing, 
  as 
  in 
  the 
  preceding, 
  the 
  

   repairs 
  of 
  injuries 
  received 
  during 
  life. 
  

  

  Fig. 
  8. 
  An 
  enlargement 
  of 
  the 
  surface, 
  showing 
  the 
  character 
  of 
  the 
  longitudi- 
  

   nal 
  striae, 
  and 
  the 
  abrupt 
  change 
  at 
  one 
  of 
  the 
  concentric 
  ridges. 
  

  

  Fig. 
  9. 
  A 
  longitudinal 
  section 
  of 
  a 
  large 
  imperfect 
  specimen, 
  showing 
  the 
  cellu- 
  

   lose 
  texture 
  of 
  the 
  substance, 
  and 
  also 
  the 
  annulated 
  character 
  of 
  

   the 
  interior 
  face 
  of 
  the 
  tube. 
  

  

  Fig. 
  10. 
  A 
  longitudinal 
  section 
  of 
  a 
  large 
  specimen, 
  where 
  the 
  walls 
  have 
  been 
  

   quite 
  thin, 
  showing 
  the 
  annulation 
  of 
  the 
  inner 
  surface 
  and 
  a 
  thin 
  

   coating 
  of 
  cellulose 
  tissue, 
  chiefly 
  on 
  one 
  side. 
  

  

  Fig. 
  11. 
  A 
  transverse 
  section 
  of 
  a 
  specimen 
  enlarged, 
  showing 
  the 
  vesicular 
  tex- 
  

   ture 
  of 
  the 
  test. 
  

  

  Fig. 
  12. 
  A 
  still 
  farther 
  enlargement 
  from 
  the 
  same 
  specimen. 
  

  

  Fig. 
  13. 
  An 
  enlargement 
  of 
  a 
  part 
  of 
  the 
  left 
  side 
  of 
  specimen 
  fig. 
  9, 
  near 
  the 
  

   middle 
  of 
  the 
  length, 
  showing 
  the 
  partial 
  obliteration 
  of 
  the 
  annu- 
  

   lations, 
  on 
  the 
  interior 
  at 
  this 
  point, 
  by 
  the 
  formation 
  of 
  vesicu- 
  

   lar 
  tissue 
  upon 
  the 
  inner 
  face. 
  This 
  change 
  is 
  probably 
  the 
  result 
  

   of 
  thickening 
  and 
  contracting 
  the 
  space 
  with 
  the 
  advancing 
  age 
  

   of 
  the 
  individual; 
  the 
  usual 
  and 
  almost 
  invariable 
  mode 
  of 
  in- 
  

   crease 
  being 
  by 
  exterior 
  additions 
  of 
  tissue. 
  

  

  Forms 
  like 
  those 
  represented 
  in 
  figures 
  1, 
  2 
  and 
  3 
  have 
  sometimes 
  been 
  

   referred 
  to 
  Cornulites, 
  Tentaculites, 
  and 
  to 
  column 
  bases 
  of 
  Cystidians. 
  More 
  

   recently 
  Prof. 
  Nicholson 
  has 
  proposed 
  the 
  names 
  Ortonia 
  and 
  Conchicolites 
  for 
  

   similar 
  forms. 
  The 
  absolute 
  connection 
  of 
  these 
  small 
  annulated 
  forms 
  with 
  

   the 
  larger 
  ones, 
  like 
  figures 
  4, 
  5, 
  6 
  and 
  7, 
  has 
  been 
  demonstrated 
  ; 
  and 
  we 
  

   find 
  the 
  smaller 
  attached 
  forms, 
  where 
  there 
  has 
  been 
  a 
  thickening 
  of 
  the 
  

   exterior, 
  and 
  a 
  partial 
  obliteration 
  of 
  the 
  regular 
  annulations, 
  giving 
  the 
  indi- 
  

   viduals 
  the 
  aspect 
  of 
  the 
  bases 
  of 
  figures 
  4 
  and 
  5. 
  Moreover, 
  longitudinal 
  

   sections 
  of 
  these 
  small 
  annulated 
  forms 
  show 
  vesicular 
  structures 
  similar 
  to 
  

   the 
  larger 
  ones. 
  In 
  one 
  example 
  before 
  me, 
  the 
  interior 
  wall 
  of 
  the 
  tube 
  is 
  

  

  