﻿P. 
  E. 
  Raymond 
  — 
  Beecher's 
  Classification 
  of 
  Trilobites. 
  199 
  

  

  on 
  the 
  Beecher 
  hypothesis 
  be 
  interpreted 
  as 
  the 
  facial 
  sutures. 
  

   Each 
  suture 
  shows 
  a 
  slight 
  outward 
  bend 
  near 
  the 
  anterior 
  

   end, 
  suggesting 
  the 
  presence 
  of 
  a 
  small 
  eye, 
  but 
  I 
  am 
  not 
  pre- 
  

   pared 
  on 
  present 
  evidence 
  to 
  say 
  that 
  eyes 
  were 
  present 
  on 
  the 
  

   ventral 
  side. 
  Jaekel's* 
  argument 
  that 
  because 
  these 
  trilobites 
  

   had 
  the 
  power 
  of 
  closing 
  the 
  pygidium 
  against 
  the 
  cephalon, 
  

   they 
  could 
  not 
  have 
  eyes 
  or 
  facial 
  sutures 
  on 
  the 
  ventral 
  side 
  

   seems 
  to 
  be 
  absolutely 
  without 
  point. 
  

  

  Swinnerton 
  also 
  cites 
  in 
  favor 
  of 
  his 
  view 
  that 
  the 
  Agnos- 
  

   tidse 
  are 
  degenerate 
  Proparia 
  with 
  fused 
  fixed 
  and 
  free 
  cheeks 
  

   and 
  obliterated 
  eyes, 
  the 
  fact 
  that 
  Walcott 
  has 
  placed 
  his 
  genus 
  

   Jlollisoniaj- 
  " 
  near 
  the 
  Agnostidse 
  " 
  (really 
  Eodiscidge) 
  and 
  in 
  

   describing 
  it 
  refers 
  to 
  indications 
  of 
  eyes 
  and 
  facial 
  sutures 
  on 
  

   the 
  dorsal 
  side. 
  I 
  have 
  only 
  the 
  published 
  figures 
  of 
  Mol- 
  

   lisonia 
  by 
  which 
  to 
  judge 
  of 
  its 
  characteristics, 
  but 
  they 
  seem 
  

   to 
  justify 
  the 
  rather 
  incomplete 
  descriptions 
  which 
  have 
  been 
  

   published, 
  and 
  I 
  do 
  not 
  see 
  that 
  any 
  importance 
  can 
  be 
  

   attached 
  to 
  them 
  in 
  connection 
  with 
  the 
  Agnostidae. 
  Indeed, 
  

   it 
  remains 
  to 
  be 
  definitely 
  shown 
  that 
  they 
  are 
  trilobites. 
  The 
  

   condition 
  of 
  preservation 
  of 
  the 
  specimens 
  indicates 
  a 
  test 
  

   unlike 
  that 
  of 
  the 
  associated 
  trilobites. 
  

  

  Summarizing 
  what 
  has 
  been 
  said 
  about 
  the 
  Agnostidge, 
  it 
  

   may 
  be 
  stated 
  that 
  interpreting 
  trilobites 
  in 
  ' 
  the 
  generally 
  ac- 
  

   cepted 
  way 
  these 
  trilobites 
  do 
  possess 
  facial 
  sutures, 
  that 
  the 
  

   sutures 
  and 
  free 
  cheeks 
  are 
  ventral 
  in 
  position, 
  and 
  the 
  posi- 
  

   tion 
  of 
  the 
  free 
  cheeks 
  is 
  such 
  that 
  these 
  trilobites, 
  had 
  they 
  

   been 
  of 
  progressive 
  stock, 
  would 
  have 
  given 
  rise 
  to 
  Proparian 
  

   descendents. 
  Since 
  the 
  free 
  cheeks 
  are 
  not 
  visible 
  from 
  the 
  

   dorsal 
  side 
  they 
  can 
  not 
  be 
  placed 
  in 
  the 
  Proparia, 
  and 
  Beecher's 
  

   order 
  Hypoparia 
  is 
  justified, 
  even 
  if 
  this 
  family 
  only 
  is 
  to 
  be 
  

   included 
  in 
  it. 
  

  

  Podiscidw. 
  — 
  The 
  discovery 
  by 
  Walcott 
  of 
  two 
  species 
  of 
  

   Eodiscids 
  with 
  free 
  cheeks 
  and 
  eyes 
  seems 
  to 
  me 
  a 
  remarkable 
  

   confirmation 
  of 
  the 
  correctness 
  of 
  the 
  position 
  to 
  which 
  Beecher 
  

   referred 
  this 
  family. 
  Pagetia% 
  is 
  an 
  undoubted 
  Eodiscid 
  and 
  

   has 
  eyes 
  very 
  far 
  from 
  the 
  glabella, 
  i. 
  e., 
  near 
  the 
  margin, 
  

   and 
  the 
  facial 
  sutures 
  are 
  short 
  and 
  have 
  a 
  typical 
  Proparian 
  

   course. 
  Now 
  this 
  is 
  exactly 
  what 
  one 
  would 
  expect 
  in 
  the 
  case 
  

   of 
  a 
  trilobite 
  in 
  which 
  the 
  eyes 
  had 
  just 
  migrated 
  over 
  the 
  lat- 
  

   eral 
  margins 
  and 
  is 
  in 
  entire 
  harmony 
  with 
  all 
  Beecher's 
  ideas. 
  

   If 
  Pagetia 
  were 
  the 
  oldest 
  known 
  genus 
  of 
  the 
  Eodiscidge, 
  one 
  

   might 
  argue 
  with 
  some 
  plausibility 
  that 
  the 
  other 
  eodiscids 
  

   w 
  T 
  ere 
  degenerate 
  from 
  such 
  a 
  state 
  of 
  development. 
  The 
  oppo- 
  

   site 
  is, 
  however, 
  true. 
  The 
  great 
  development 
  of 
  the 
  Eodisci- 
  

  

  *Op. 
  cit., 
  p. 
  388. 
  

  

  f 
  Smithsonian 
  Miscl. 
  Coll., 
  vol. 
  lvii, 
  p. 
  195, 
  pi. 
  24, 
  fig. 
  3, 
  1912. 
  

  

  X 
  Ibid., 
  vol. 
  lxiv, 
  No. 
  5, 
  p. 
  408, 
  pi. 
  67, 
  1916. 
  

  

  