﻿art 
  9 
  UNUSUAL 
  FORMS 
  OF 
  FOSSIL 
  CRINOIDS 
  SPRINGER 
  63 
  

  

  Five 
  may 
  be 
  accepted 
  distinguished 
  by 
  well 
  defined 
  special 
  char- 
  

   acters, 
  some 
  of 
  which 
  may 
  be 
  only 
  individual 
  variations, 
  namely 
  : 
  

  

  1. 
  A. 
  conicus 
  Owen 
  and 
  Shuinard, 
  by 
  its 
  strictly 
  conical 
  and 
  very 
  elongate 
  

   form, 
  large 
  size, 
  and 
  great 
  relative 
  height 
  of 
  the 
  infrabasal 
  cone, 
  which 
  is 
  

   more 
  than 
  half 
  the 
  height 
  of 
  the 
  calyx 
  (pi. 
  15, 
  fig. 
  1). 
  

  

  2. 
  A. 
  laevis 
  Roenier, 
  by 
  its 
  broadly 
  rounded, 
  ovoid 
  calyx, 
  of 
  which 
  the 
  base 
  

   is 
  more 
  than 
  one-third 
  its 
  height 
  (pi. 
  15, 
  fig. 
  5) 
  ; 
  this 
  includes 
  Troost's 
  Ms. 
  

   species, 
  A 
  dactyliformis, 
  and 
  the 
  specimen 
  figured 
  by 
  Meek 
  and 
  Worthen 
  in 
  

   Illinois 
  (vol. 
  5, 
  pi. 
  21, 
  fig. 
  7). 
  

  

  3. 
  A. 
  constrictus 
  Hall, 
  by 
  its 
  very 
  elongate, 
  narrow 
  calyx, 
  and 
  constricted 
  

   base. 
  

  

  4. 
  A. 
  pentagonus 
  Worthen, 
  by 
  its 
  pentagonal 
  outline, 
  and 
  concave 
  basal 
  

   plates. 
  

  

  5. 
  A. 
  dissimilis 
  Weller, 
  by 
  its 
  deeply 
  incised 
  sutures. 
  

   Nos. 
  1, 
  2, 
  and 
  5 
  have 
  the 
  infrabasals 
  fused. 
  

  

  Of 
  the 
  remaining 
  species, 
  which 
  include 
  three 
  synonyms, 
  six 
  might 
  

   be 
  arranged, 
  for 
  want 
  of 
  any 
  better 
  criterion, 
  according 
  to 
  the 
  gen- 
  

   eral 
  form 
  of 
  the 
  calyx 
  as 
  used 
  in 
  many 
  of 
  the 
  descriptions, 
  whether 
  

   subconical, 
  ovoid, 
  or 
  globose; 
  to 
  which 
  may 
  be 
  usefully 
  added 
  the 
  

   relative 
  height 
  of 
  the 
  infrabasal 
  cone 
  or 
  disk: 
  

  

  6. 
  A. 
  gibbosus 
  Hall, 
  syn. 
  A. 
  chesterensis 
  Worthen 
  ; 
  subcorneal, 
  but 
  much 
  more 
  

   rounded 
  and 
  less 
  elongate 
  than 
  conicus, 
  both 
  as 
  to 
  the 
  entire 
  calyx 
  and 
  the 
  

   infrabasal 
  cone, 
  the 
  height 
  being 
  slightly 
  more 
  than 
  the 
  greatest 
  width, 
  and 
  

   the 
  infrabasals 
  one-fourth 
  to 
  one-third 
  the 
  height 
  of 
  calyx; 
  infrabasals 
  fused 
  

   (pi. 
  15, 
  fig. 
  8). 
  

  

  Widely 
  distributed, 
  found 
  in 
  all 
  the 
  principal 
  Chester 
  areas. 
  

  

  7. 
  A. 
  inequidactylus 
  (Whitfield) 
  ; 
  similar 
  to 
  last, 
  only 
  having 
  infrabasals 
  

   divided 
  and 
  a 
  column 
  ; 
  and 
  being 
  more 
  elongate 
  and 
  more 
  distinctly 
  conical 
  

   in 
  form 
  (pi. 
  15, 
  figs. 
  10-13). 
  

  

  8. 
  A. 
  papillatus 
  Worthen, 
  syn. 
  A. 
  hemispJuricus 
  Worthen; 
  and 
  (?) 
  A. 
  oc- 
  

   cidentalis 
  Owen 
  and 
  Shumard 
  ; 
  calyx 
  globose, 
  wider 
  than 
  high 
  ; 
  infrabasals 
  

   forming 
  a 
  low 
  disk, 
  less 
  than 
  one-fourth 
  the 
  height 
  of 
  calyx, 
  divided, 
  with 
  a 
  

   column 
  facet. 
  A. 
  occidentalis 
  is 
  included 
  here 
  with 
  a 
  ( 
  ? 
  ) 
  ; 
  if 
  the 
  characters 
  

   were 
  certain 
  it 
  would 
  have 
  to 
  head 
  the 
  group, 
  being 
  earliest 
  in 
  date. 
  Prob- 
  

   ably 
  from 
  the 
  Paint 
  Creek 
  formation, 
  a 
  lower 
  horizon 
  than 
  all 
  the 
  others 
  

   except 
  No. 
  5. 
  

  

  9. 
  A. 
  globosas 
  Worthen 
  ; 
  characters 
  not 
  materially 
  different 
  from 
  the 
  last, 
  

   but 
  it 
  is 
  slightly 
  larger, 
  and 
  from 
  a 
  higher 
  horizon, 
  being 
  characteristic 
  of 
  the 
  

   Gasper 
  formation, 
  especially 
  in 
  Breckrenridge 
  County, 
  Kentucky 
  (pi. 
  15, 
  fig. 
  

   14). 
  

  

  10. 
  A. 
  ovalis 
  Miller 
  and 
  Gurley; 
  same 
  as 
  last, 
  except 
  that 
  while 
  the 
  figures 
  

   show 
  divided 
  infrabasals, 
  the 
  descriptions 
  say 
  there 
  is 
  no 
  evidence 
  of 
  a 
  column 
  

   (pi. 
  15, 
  figs. 
  15, 
  16, 
  17). 
  

  

  11. 
  Agassizocrinus 
  lobatus, 
  new 
  species. 
  A 
  thoroughly 
  distinct 
  species, 
  from 
  

   the 
  Gasper 
  formation 
  at 
  Huntsville, 
  Alabama, 
  represented 
  by 
  12 
  specimens 
  

   that 
  only 
  came 
  to 
  light 
  in 
  the 
  collection 
  after 
  the 
  foregoing 
  discussion 
  was 
  

   prepared. 
  It 
  is 
  remarkable 
  for 
  having 
  the 
  infrabasal 
  cup 
  (which 
  is 
  the 
  only 
  

   part 
  known) 
  strongly 
  lobed 
  next 
  to 
  the 
  top, 
  and 
  more 
  or 
  less 
  divided, 
  while 
  

   it 
  is 
  rounded 
  and 
  fused 
  at 
  the 
  bottom. 
  I 
  have 
  figured 
  a 
  set 
  of 
  six 
  of 
  the 
  

   cups 
  in 
  which 
  these 
  characters 
  are 
  fully 
  shown 
  (pi. 
  26, 
  figs. 
  13-18). 
  

  

  