﻿art 
  9 
  UNUSUAL 
  FORMS 
  OF 
  FOSSIL 
  CRINOIDS 
  SPRINGER 
  17 
  

  

  umnals. 
  Crown 
  small, 
  superficially 
  resembling 
  loerinus, 
  but 
  calyx 
  

   elements 
  not 
  fully 
  known. 
  

  

  Hall's 
  description 
  has 
  scarcely 
  anj^thing 
  of 
  diagnostic 
  value, 
  be- 
  

   ing 
  based, 
  like 
  that 
  of 
  eonvolutus, 
  upon 
  the 
  idea 
  that 
  the 
  fossils 
  be- 
  

   fore 
  him 
  were 
  the 
  arms 
  of 
  a 
  crinoid. 
  But 
  his 
  figures 
  clearly 
  show 
  

   the 
  important 
  fact 
  that 
  the 
  cirri 
  are 
  few, 
  originating 
  at 
  alternate 
  

   intervals 
  from 
  the 
  back 
  of 
  the 
  stem. 
  These 
  characters 
  enable 
  us 
  

   readily 
  to 
  identify 
  the 
  prevalent 
  form 
  of 
  the 
  genus 
  occurring 
  in 
  the 
  

   Rochester 
  shale 
  at 
  Lockport, 
  New 
  York. 
  I 
  have 
  upwards 
  of 
  seventy 
  

   specimens, 
  assembled 
  from 
  the 
  extensive 
  collection 
  of 
  Doctor 
  Ringue- 
  

   berg, 
  and 
  the 
  fruits 
  of 
  three 
  seasons' 
  work 
  in 
  the 
  shales 
  at 
  Lockport 
  

   by 
  Frederick 
  Braun. 
  This 
  material 
  brings 
  out 
  the 
  further 
  remark- 
  

   able 
  fact, 
  unknown 
  to 
  Hall, 
  that 
  the 
  cirri 
  are 
  branching 
  — 
  a 
  charac- 
  

   ter 
  which 
  I 
  believe 
  to 
  be 
  hitherto 
  unknown 
  in 
  any 
  crinoid, 
  fossil 
  or 
  

   recent, 
  except 
  in 
  cases 
  where 
  the 
  cirri 
  belong 
  strictly 
  to 
  the 
  root. 
  11 
  

  

  This 
  fact 
  emphasizes 
  the 
  broad 
  distinction 
  between 
  the 
  two 
  

   original 
  species 
  from 
  the 
  type 
  locality, 
  the 
  characters 
  of 
  M. 
  con- 
  

   volutus 
  being 
  in 
  strong 
  contrast 
  to 
  those 
  of 
  M. 
  brachiatus 
  in 
  almost 
  

   every 
  particular. 
  Instead 
  of 
  the 
  cirri 
  being 
  short, 
  flat, 
  numerous, 
  

   and 
  extending 
  well 
  toward 
  the 
  proximal 
  region, 
  as 
  in 
  the 
  former 
  

   species, 
  here 
  there 
  are 
  but 
  few 
  of 
  them, 
  at 
  intervals 
  of 
  several 
  

   columnals, 
  springing 
  from 
  the 
  back 
  instead 
  of 
  the 
  lateral 
  margins, 
  

   and 
  restricted 
  to 
  the 
  distal 
  region 
  of 
  the 
  stem. 
  But 
  what 
  they 
  lack 
  

   in 
  number 
  they 
  make 
  up 
  in 
  size. 
  Notwithstanding 
  the 
  fine 
  preserva- 
  

   tion 
  of 
  many 
  of 
  the 
  specimens, 
  in 
  which 
  the 
  strong, 
  round 
  cirri 
  

   are 
  present 
  to 
  the 
  extent 
  of 
  several 
  branches, 
  it 
  is 
  doubtful 
  if 
  we 
  

   have 
  the 
  cirri 
  preserved 
  to 
  their 
  full 
  length 
  in 
  any 
  of 
  them- 
  But 
  it 
  

   is 
  evident 
  that 
  in 
  many 
  cases 
  — 
  perhaps 
  always 
  — 
  they 
  exceeded 
  in 
  

   length 
  the 
  entire 
  elliptic 
  or 
  crescentic 
  portion 
  of 
  the 
  stem, 
  so 
  that 
  

   with 
  their 
  numerous 
  branches 
  they 
  formed 
  a 
  complete 
  fringe, 
  by 
  

   which 
  when 
  retracted 
  by 
  its 
  slender 
  neck 
  the 
  crown 
  was 
  surrounded 
  

   without 
  being 
  closely 
  infolded 
  as 
  in 
  convolutus 
  and 
  species 
  of 
  

   similar 
  type 
  We 
  have 
  the 
  stem 
  preserved 
  to 
  the 
  distal 
  end, 
  where 
  

   it 
  becomes 
  round 
  and 
  tapers 
  rapidly 
  to 
  a 
  point. 
  

  

  Among 
  the 
  material 
  obtained 
  by 
  Braun 
  during 
  his 
  campaigns 
  

   at 
  Lockport 
  in 
  the 
  years 
  1910, 
  1911, 
  and 
  1914, 
  were 
  a 
  number 
  of 
  

   specimens 
  in 
  which 
  the 
  thick 
  distal 
  and 
  median 
  portion 
  of 
  the 
  stem 
  

   was 
  seen 
  imbedded 
  in 
  a 
  fine-grained 
  matrix 
  favorable 
  for 
  prepara- 
  

   tion. 
  Upon 
  carefully 
  following 
  this 
  up, 
  I 
  came 
  first 
  to 
  the 
  slender 
  

  

  "A 
  figure 
  in 
  Goldfuss 
  (Potrof. 
  Germ., 
  vol. 
  1, 
  1829, 
  p. 
  190, 
  pi. 
  58, 
  T. 
  fig. 
  7, 
  Z), 
  under 
  

   the 
  heading 
  of 
  Cyathocrinus 
  pinnatus 
  Goldfuss, 
  of 
  a 
  fragment 
  from 
  the 
  Devonian 
  of 
  the 
  

   Rheinland, 
  seems 
  to 
  show 
  a 
  coiled 
  bilateral 
  stem, 
  with 
  two 
  marginal 
  rows 
  of 
  cirri, 
  which 
  

   fork 
  at 
  a 
  distance 
  of 
  several 
  ossicles 
  from 
  the 
  stem. 
  There 
  is 
  nothing 
  to 
  indicate 
  its 
  rela- 
  

   tion 
  to 
  other 
  forms, 
  not 
  even 
  to 
  the 
  other 
  fragments 
  figured 
  under 
  the 
  same 
  name 
  ; 
  and 
  it 
  

   may 
  be 
  an 
  arm 
  trunk 
  of 
  some 
  Melocrinid. 
  

  

  