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  muscular 
  impressions 
  indistinct 
  or 
  absent 
  ; 
  no 
  articular 
  ridge 
  ; 
  no 
  

   canal-aperture. 
  Arms 
  unknown 
  ; 
  ? 
  represented 
  by 
  fleshy 
  append- 
  

   ages. 
  Calycal 
  cavity 
  contained 
  in 
  first 
  radials 
  ; 
  with 
  small 
  round 
  

   ventral 
  aperture, 
  surrounded 
  by 
  a 
  rim 
  which 
  is 
  the 
  only 
  relic 
  of 
  a 
  

   muscular 
  attachment. 
  Stem 
  unknown. 
  

  

  It 
  is 
  hard 
  to 
  see 
  how 
  the 
  animal 
  obtained 
  its 
  food 
  ; 
  and 
  this 
  

   suggests 
  that 
  it 
  was 
  free-swimming, 
  an 
  idea 
  countenanced 
  by 
  the 
  

   great 
  lightness 
  and 
  strength 
  of 
  the 
  calyx. 
  On 
  the 
  other 
  hand, 
  arms 
  

   unfit 
  for 
  obtaining 
  food 
  must 
  have 
  been 
  still 
  more 
  unfit 
  for 
  swim- 
  

   ming. 
  Further, 
  to 
  take 
  to 
  a 
  free 
  life 
  is 
  a 
  progressive 
  development, 
  

   and 
  analogy 
  renders 
  it 
  unlikely 
  that 
  such 
  a 
  form 
  should 
  be 
  the 
  

   last 
  of 
  its 
  race. 
  This 
  latter 
  argument 
  also 
  prevents 
  us 
  from 
  sup- 
  

   posing 
  that 
  the 
  animal 
  was 
  parasitic 
  on 
  some 
  soft-bodied 
  creature, 
  

   to 
  which 
  mode 
  of 
  life 
  its 
  structure 
  seems 
  admirably 
  adapted. 
  

   We 
  can 
  only 
  suppose 
  that 
  Trigonocrinus 
  was 
  a 
  form 
  degenerate, 
  

   not 
  owing 
  to 
  conditions 
  or 
  to 
  any 
  mode 
  of 
  natural 
  selection, 
  and 
  not 
  

   from 
  any 
  fault 
  of 
  its 
  own, 
  but 
  in 
  obedience 
  to 
  those 
  laws, 
  as 
  yet 
  

   half 
  understood, 
  that 
  govern 
  the 
  life 
  of 
  a 
  race 
  no 
  less 
  than 
  of 
  an 
  

   individual. 
  

  

  Of 
  this 
  genus 
  only 
  one 
  species 
  is 
  known. 
  

  

  Trigonocrinus 
  liratus, 
  sp. 
  nov. 
  

  

  Calyx 
  rather 
  more 
  elongate 
  than 
  in 
  the 
  known 
  species 
  of 
  Phyllo- 
  

   crinus 
  ; 
  basals 
  ornamented 
  with 
  minute 
  granules 
  ; 
  radials 
  ornamented 
  

   with 
  similar 
  granules 
  run 
  into 
  curved- 
  ridges, 
  which, 
  owing 
  to 
  their 
  

   differing 
  intensity, 
  give 
  an 
  imbricated 
  appearance 
  ; 
  spines 
  triangular 
  

   in 
  section, 
  with 
  the 
  base 
  of 
  the 
  triangle 
  directed 
  inwards, 
  the 
  apex 
  

   outwards, 
  the 
  angles 
  often 
  rounded. 
  

  

  In 
  describing 
  a 
  totally 
  new 
  genus 
  from 
  only 
  two 
  specimens, 
  both 
  

   of 
  the 
  same 
  species, 
  it 
  is 
  hard, 
  if 
  not 
  impossible, 
  to 
  discriminate 
  

   generic, 
  specific, 
  and 
  merely 
  varietal 
  characters 
  ; 
  but 
  an 
  examination 
  

   of 
  the 
  species 
  in 
  other 
  genera 
  of 
  Eugeniacrinidae 
  leads 
  me 
  to 
  believe 
  

   that 
  the 
  above 
  characters 
  are 
  of 
  specific 
  value. 
  

  

  I 
  have 
  referred 
  this 
  genus 
  without 
  hesitation 
  to 
  the 
  Eugeniacri- 
  

   nidae 
  ; 
  at 
  the 
  same 
  time 
  it 
  is 
  clear 
  that 
  its 
  adoption 
  will 
  necessitate 
  

   a 
  rewriting 
  of 
  the 
  existing 
  description 
  of 
  that 
  family, 
  even 
  of 
  that 
  

   by 
  Prof. 
  v. 
  Zittel. 
  This, 
  of 
  course, 
  does 
  not 
  mean 
  that 
  the 
  family 
  

   Eugeniacrinidae 
  is 
  not 
  a 
  perfectly 
  good 
  one 
  — 
  it 
  is 
  merely 
  one 
  more 
  

   instance 
  of 
  the 
  great 
  difficulty 
  of 
  defining 
  any 
  natural 
  assemblage 
  of 
  

   living 
  beings, 
  so 
  as 
  to 
  include 
  all 
  forms 
  connected 
  with 
  it 
  by 
  direct 
  

   blood-relationship. 
  Should 
  this 
  paper 
  instigate, 
  as 
  I 
  hope 
  it 
  will, 
  

   renewed 
  research 
  among 
  the 
  fossil-beds 
  of 
  Wiirtemberg 
  and 
  Bavaria, 
  

   it 
  is 
  possible 
  that 
  more 
  allied 
  forms 
  may 
  be 
  found. 
  The 
  task 
  of 
  re- 
  

   definition 
  is 
  therefore 
  better 
  left 
  over 
  for 
  the 
  present, 
  with 
  the 
  

   added 
  hope 
  that 
  it 
  may 
  fall 
  into 
  more 
  competent 
  hands. 
  

  

  Deviation 
  from 
  a 
  Pentamerotjs 
  Type. 
  

  

  It 
  is 
  impossible 
  to 
  leave 
  this 
  striking 
  form 
  without 
  some 
  remarks 
  

   on 
  its 
  most 
  remarkable 
  character, 
  namely, 
  the 
  complete 
  loss 
  of 
  one 
  

   Q. 
  J. 
  G. 
  S. 
  No. 
  177. 
  m 
  

  

  