﻿art 
  9 
  UNUSUAL. 
  FORMS 
  OF 
  FOSSIL 
  CRINOIDS 
  SPRINGER 
  75 
  

  

  The 
  species 
  Aulocrinus 
  agassizi 
  is 
  strongly 
  characterized 
  by 
  sharp 
  

   and 
  prominent 
  wrinkles 
  upon 
  the 
  calyx 
  plates; 
  the 
  angular 
  and 
  

   keeled 
  brachials 
  ; 
  the 
  well 
  defined 
  pores 
  at 
  the 
  sides 
  of 
  the 
  hexagonal 
  

   tube 
  plates; 
  and 
  the 
  sharp 
  longitudinal 
  columns 
  in 
  which 
  these 
  

   plates 
  are 
  arranged. 
  The 
  stem 
  is 
  sharply 
  pentagonal, 
  and 
  is 
  pro- 
  

   vided 
  with 
  strong 
  cirri, 
  which 
  are 
  not 
  shown 
  upon 
  the 
  plate 
  for 
  

   want 
  of 
  space. 
  The 
  species 
  is 
  represented 
  by 
  ten 
  specimens, 
  six 
  of 
  

   which 
  show 
  the 
  lateral 
  spout. 
  I 
  am 
  figuring 
  a 
  series 
  of 
  these 
  to 
  show 
  

   all 
  aspects 
  of 
  the 
  remarkable 
  structures, 
  including 
  a 
  posterior 
  view 
  

   of 
  the 
  tube 
  to 
  its 
  full 
  length, 
  and 
  three 
  views 
  of 
  the 
  spout 
  in 
  such 
  

   positions 
  as 
  enable 
  us 
  to 
  trace 
  the 
  longitudinal 
  ridges 
  along 
  the 
  tube 
  

   past 
  the 
  point 
  where 
  it 
  doubles 
  upon 
  itself 
  and 
  branches 
  backward 
  

   into 
  the 
  spout. 
  Especially 
  instructive 
  in 
  this 
  respect 
  is 
  the 
  broken 
  

   specimen 
  (fig. 
  3), 
  in 
  which 
  the 
  ridges 
  may 
  be 
  followed 
  without 
  in- 
  

   terruption. 
  

  

  ULRICHICRINUS, 
  new 
  genus 
  

  

  Plate 
  20 
  

   Upper 
  Carboniferous; 
  Pennsylvania]!. 
  

  

  Between 
  Pachylocrinus, 
  Scytalocrinios, 
  and 
  Woodocrinm. 
  Of 
  a 
  

   f 
  acies 
  somewhat 
  similar 
  to 
  that 
  of 
  Scytalocrinus, 
  but 
  has 
  more 
  than 
  

   10 
  long, 
  slender, 
  unbranched 
  arms, 
  bifurcating 
  on 
  the 
  IIBr, 
  both 
  or 
  

   only 
  one, 
  giving 
  4 
  or 
  3 
  arms 
  to 
  the 
  ray. 
  Brachials 
  cuneiform, 
  which 
  

   distinguishes 
  it 
  from 
  Woodocrinus, 
  as 
  also 
  does 
  the 
  great 
  relative 
  

   difference 
  in 
  size 
  of 
  the 
  arms. 
  It 
  has 
  too 
  many 
  bifurcations 
  for 
  

   Scytalocrinus 
  and 
  not 
  enough 
  for 
  Pachylocrinus. 
  Calyx 
  conical, 
  

   spreading 
  from 
  the 
  base 
  about 
  the 
  same 
  as 
  in 
  the 
  turbinate 
  Poterio- 
  

   crininae 
  generally. 
  The 
  tube 
  has 
  not 
  been 
  exposed, 
  but 
  from 
  the 
  

   elongate 
  series 
  of 
  strong 
  anal 
  plates 
  it 
  is 
  undoubtedly 
  of 
  the 
  type 
  of 
  

   the 
  related 
  genera. 
  

  

  This 
  genus 
  is 
  proposed 
  for 
  the 
  reception 
  of 
  a 
  species 
  from 
  the 
  

   Morrow 
  formation 
  of 
  Oklahoma, 
  based 
  upon 
  specimens 
  collected 
  

   many 
  years 
  ago 
  by 
  Dr. 
  E. 
  O. 
  Ulrich, 
  while 
  engaged 
  in 
  field 
  work 
  

   for 
  the 
  U. 
  S. 
  Geological 
  Survey, 
  and 
  now 
  placed 
  in 
  my 
  hands 
  for 
  

   description 
  by 
  Dr. 
  George 
  T. 
  Girty, 
  in 
  charge 
  of 
  Carboniferous 
  re- 
  

   searches 
  for 
  the 
  Survey, 
  which 
  I 
  have 
  been 
  unable 
  to 
  place 
  under 
  any 
  

   of 
  the 
  described 
  genera. 
  It 
  was, 
  however, 
  found 
  to 
  be 
  congeneric 
  

   with 
  a 
  well 
  marked 
  species 
  from 
  the 
  Keokuk 
  of 
  Indiana 
  described 
  by 
  

   S. 
  A. 
  Miller 
  as 
  Poteriocrinas 
  coryphaeus, 
  which 
  while 
  represented 
  by 
  

   numerous 
  good 
  specimens 
  has 
  always 
  made 
  trouble 
  in 
  the 
  collections 
  

   because 
  it 
  would 
  not 
  fit 
  exactly 
  under 
  any 
  known 
  genus. 
  With 
  this 
  

   addition 
  the 
  new 
  genus 
  is 
  well 
  distributed. 
  I 
  have 
  pleasure 
  in 
  as- 
  

   sociating 
  Avith 
  this 
  interesting 
  form 
  the 
  name 
  of 
  the 
  discoverer, 
  my 
  

   neighbor 
  and 
  colleague, 
  Dr. 
  E. 
  O. 
  Ulrich, 
  of 
  the 
  United 
  States 
  

   National 
  Museum, 
  and 
  United 
  States 
  Geological 
  Survev. 
  

  

  