﻿art 
  9 
  UNUSUAL 
  FORMS 
  OF 
  FOSSIL 
  CRINOIDS 
  — 
  SPRINGER 
  31 
  

  

  Horizon 
  and 
  locality. 
  — 
  Mississippian, 
  Keokuk 
  limestone, 
  upper 
  

   horizon 
  ; 
  Crawfordsville, 
  Indiana. 
  

  

  CAMPTOCRINUS 
  MULTICIRRUS, 
  new 
  species 
  

  

  Plate 
  8, 
  figs. 
  4-9 
  

  

  Camptocrinus 
  cirri 
  fcr 
  Wachsmuth 
  and 
  Springer 
  North 
  Amer. 
  Criu. 
  Cam., 
  

   1897, 
  pi. 
  76, 
  fig. 
  13c 
  (not 
  13a, 
  6.). 
  

  

  Stem 
  long, 
  tapering 
  almost 
  to 
  a 
  point, 
  becoming 
  round 
  and 
  very 
  

   slender 
  at 
  the 
  distal 
  end, 
  but 
  throughout 
  the 
  middle 
  region 
  strongly- 
  

   elliptic, 
  and 
  maintaining 
  a 
  nearly 
  uniform 
  width. 
  Cirri 
  doubled 
  

   or 
  in 
  clusters 
  of 
  3, 
  diminishing 
  inward 
  ; 
  exceptionally 
  single, 
  spring- 
  

   ing 
  from 
  each 
  end 
  of 
  pairs 
  of 
  short 
  nodal 
  columnals 
  alternating 
  

   with 
  a 
  long 
  internodal 
  as 
  in 
  C. 
  myelodactylus 
  ; 
  they 
  are 
  rounded, 
  

   long 
  and 
  slender, 
  composed 
  when 
  complete 
  of 
  upwards 
  of 
  30 
  cirrals, 
  

   mostly 
  longer 
  than 
  wide. 
  Besides 
  the 
  prominent 
  marginal 
  cirri 
  in 
  

   two 
  rows 
  at 
  the 
  concave 
  side 
  of 
  the 
  stem, 
  additional 
  cirri 
  occur 
  at 
  

   the 
  back 
  in 
  many 
  places 
  tending 
  to 
  form 
  whorls; 
  these 
  secondary 
  

   cirri 
  are 
  much 
  smaller 
  than 
  the 
  others 
  and 
  appear 
  in 
  a 
  variety 
  of 
  

   rudimentary 
  stages. 
  Some 
  have 
  two, 
  three 
  or 
  four 
  cirrals; 
  many 
  

   have 
  only 
  the 
  first 
  cirral 
  remaining, 
  but 
  pierced 
  by 
  the 
  axial 
  canal, 
  

   indicating 
  that 
  one 
  or 
  more 
  others 
  followed; 
  still 
  others, 
  rather 
  

   numerous, 
  have 
  the 
  first 
  cirral 
  imperfect 
  with 
  no 
  axial 
  canal, 
  but 
  

   rounded 
  off 
  like 
  a 
  terminal 
  ossicle, 
  as 
  if 
  it 
  had 
  just 
  broken 
  through 
  

   without 
  being 
  able 
  to 
  grow 
  farther. 
  These 
  details 
  are 
  fully 
  shown 
  

   by 
  the 
  instructive 
  sketches 
  made 
  from 
  the 
  two 
  remarkably 
  perfect 
  

   specimens 
  figured 
  on 
  plate 
  8 
  (figs. 
  4, 
  4<7, 
  6, 
  6«). 
  The 
  proximal 
  cir- 
  

   cular 
  neck 
  is 
  relatively 
  short, 
  and 
  the 
  crown 
  is 
  not 
  closely 
  enveloped 
  

   by 
  the 
  cirri. 
  The 
  calyx 
  is 
  shorter 
  than 
  in 
  G. 
  crawfordsvillensis, 
  

   especially 
  the 
  basal 
  plates, 
  which 
  are 
  not 
  over 
  one-fourth 
  the 
  height 
  

   of 
  the 
  cup; 
  they 
  are 
  frequently 
  deformed 
  owing 
  to 
  compression 
  by 
  

   the 
  curved 
  stem, 
  so 
  that 
  they 
  are 
  shorter 
  at 
  one 
  side 
  than 
  the 
  other, 
  

   as 
  shown 
  in 
  figure 
  4 
  of 
  plate 
  8. 
  Arms 
  two 
  to 
  the 
  ray, 
  uniserial 
  

   with 
  more 
  or 
  less 
  cuneate 
  ossicles; 
  rather 
  longer 
  than 
  is 
  usual 
  in 
  

   Dichocrinus. 
  

  

  Dimensions 
  of 
  a 
  maximum 
  specimen: 
  Total 
  length 
  of 
  stem, 
  12.5 
  

   cm. 
  ; 
  of 
  circular 
  neck 
  10 
  mm. 
  ; 
  long 
  diameter 
  of 
  columnal 
  in 
  middle 
  

   portion 
  2.5 
  mm. 
  ; 
  short 
  diameter 
  1.5 
  mm. 
  ; 
  diameter 
  at 
  circular 
  neck 
  

   1 
  mm.; 
  at 
  distal 
  end, 
  rounded 
  almost 
  to 
  a 
  point, 
  .5 
  mm. 
  

  

  This 
  is 
  the 
  most 
  abundant 
  and 
  widely 
  distributed 
  species 
  of 
  the 
  

   genus, 
  being 
  represented 
  in 
  the 
  collection 
  by 
  upwards 
  of 
  thirty 
  

   specimens 
  from 
  two 
  well 
  separated 
  areas, 
  namely, 
  that 
  of 
  Hunts- 
  

   ville, 
  Alabama, 
  and 
  of 
  Monroe 
  county, 
  Illinois. 
  It 
  occurs 
  in 
  the 
  

   lower 
  part 
  of 
  the 
  Chester, 
  in 
  the 
  Ohara 
  formation 
  at 
  Huntsville, 
  

   and 
  in 
  what 
  is 
  regarded 
  as 
  its 
  equivalent 
  formation 
  at 
  the 
  Illinois 
  

  

  