﻿OrnltJiosaurian 
  Genus 
  Oniitlioclieirus. 
  533 
  

  

  characters 
  found 
  amongst 
  this 
  medley 
  of 
  bones 
  and 
  those 
  of 
  

   the 
  pterodactyls 
  of 
  the 
  Chalk 
  of 
  Kansas. 
  Its 
  effect 
  is 
  seoi 
  

   when 
  Professor 
  Williston 
  "^ 
  remarks 
  that 
  ''every 
  essential 
  

   character 
  that 
  has 
  been 
  given 
  so 
  far 
  for 
  the 
  European 
  species 
  

   of 
  this 
  group 
  agrees 
  quite 
  with 
  those 
  of 
  our 
  Kansas 
  speci- 
  

   mens. 
  Tills 
  will 
  demonstrate 
  how 
  unimportant 
  are 
  the 
  

   characters 
  derived 
  from 
  the 
  absence 
  or 
  presence 
  of 
  teeth." 
  

  

  lu 
  the 
  present 
  case 
  the 
  absence 
  or 
  presence 
  of 
  teeth 
  affords 
  

   a 
  certain 
  character^ 
  although 
  amongst 
  Icthyosaurs 
  and 
  Aves 
  

   it 
  has 
  been 
  shown 
  to 
  be 
  not 
  dependable. 
  Therefore 
  it 
  would 
  

   be 
  extremely 
  unwise 
  to 
  follow 
  this 
  rule 
  too 
  closely, 
  for 
  a 
  

   toothed 
  condition 
  is 
  a 
  more 
  primitive 
  character 
  in 
  this 
  

   respect 
  than 
  a 
  toothless. 
  We 
  must 
  make 
  use 
  of 
  the 
  features 
  

   we 
  have 
  at 
  command 
  when 
  dealing 
  with 
  such 
  fragmentary 
  

   remains. 
  Moreover, 
  at 
  the 
  time 
  of 
  the 
  deposition 
  of 
  the 
  

   Cambridge 
  Greensand 
  they 
  were 
  an 
  expiring 
  race 
  and 
  near 
  

   the 
  end 
  of 
  their 
  line, 
  and 
  thus 
  Ave 
  are 
  examining 
  the 
  fixed 
  or 
  

   degraded 
  characters 
  of 
  the 
  ultimate 
  descendants, 
  and 
  not 
  the 
  

   ancestors. 
  Therefore 
  the 
  peculiarities 
  obtaining 
  have 
  a 
  

   greater 
  value 
  than 
  if 
  found 
  in 
  the 
  beginners, 
  for 
  they 
  are 
  

   the 
  specialized 
  result 
  of 
  natural 
  selection 
  acting 
  through 
  

   ages. 
  The 
  situation 
  of 
  the 
  front 
  pair 
  of 
  teeth 
  in 
  some 
  jaws, 
  

   right 
  above 
  the 
  palate 
  on 
  the 
  anterior 
  face 
  of 
  the 
  beak, 
  we 
  

   shall 
  shortly 
  show 
  is 
  an 
  accident 
  caused 
  by 
  the 
  wearing 
  

   away 
  of 
  the 
  snout. 
  Those 
  without 
  teeth 
  must 
  for 
  a 
  great 
  

   period 
  have 
  diverged 
  from 
  those 
  ivitli 
  teeth. 
  The 
  fact 
  that 
  

   the 
  seizure 
  and 
  prehension 
  of 
  food 
  are 
  obtained 
  by 
  such 
  

   opposite 
  means 
  argues 
  of 
  itself 
  corresponding 
  variations 
  in 
  

   the 
  form 
  of 
  the 
  bones 
  of 
  the 
  skull. 
  In 
  the 
  Cambridge 
  

   material 
  many 
  of 
  the 
  teeth 
  are 
  grooved 
  and 
  circular, 
  and 
  

   certainly 
  more 
  simple 
  and 
  less 
  specialized 
  than 
  the 
  remainder, 
  

   which 
  are 
  more 
  or 
  less 
  compressed 
  laterally, 
  with 
  an 
  absence 
  

   of 
  grooving. 
  To 
  conclude 
  that 
  the 
  odd 
  bones 
  belonged 
  to 
  

   the 
  same 
  individuals, 
  or 
  even 
  to 
  the 
  identical 
  genus, 
  as 
  the 
  

   fragments 
  of 
  skulls, 
  because 
  they 
  happen 
  to 
  be 
  found 
  on 
  the 
  

   same 
  horizon, 
  is 
  a 
  dangerous 
  means 
  of 
  diagnosis, 
  and 
  has 
  not 
  

   infrequently 
  led 
  to 
  error 
  in 
  the 
  past. 
  This 
  danger 
  is 
  inten, 
  

   sified 
  when 
  we 
  remember 
  that 
  the 
  Cambridge 
  Greensand 
  is 
  

   the 
  remains 
  of 
  an 
  old 
  shore-line, 
  where 
  bones 
  of 
  these 
  

   creatixres 
  accumulated, 
  not 
  oid}^ 
  from 
  those 
  contemporaneous, 
  

   but 
  also 
  probably 
  from 
  those 
  derived 
  from 
  older 
  beds, 
  and 
  

   could 
  not 
  have 
  formed 
  even 
  a 
  tithe 
  of 
  the 
  flocks 
  of 
  these 
  

   reptiles 
  inhabiting 
  the 
  district. 
  

  

  * 
  S. 
  W. 
  Williston, 
  " 
  Ilestoration 
  of 
  Ornithostoma,'' 
  Kansas 
  Quarterly, 
  

   18',)7, 
  p. 
  35. 
  

  

  