﻿116 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  L. 
  macropus 
  one-half, 
  and 
  Coelosaurus 
  antiquus 
  one 
  fourth 
  or 
  fifth 
  the 
  size, 
  whose 
  remains 
  

   so 
  far 
  as 
  they 
  go 
  indicate 
  an 
  identity 
  of 
  habit. 
  Deslongchamps 
  says 
  of 
  Poecilopleurum 
  

   bucklandii 
  that 
  it 
  " 
  could 
  project 
  itself 
  with 
  prodigious 
  force, 
  as 
  a 
  spring 
  which 
  unbends 
  

   itself; 
  but 
  this 
  could 
  not 
  have 
  been 
  on 
  a 
  solid 
  surface, 
  since 
  the 
  fore 
  limbs 
  are 
  too 
  weak 
  

   to 
  resist 
  the 
  shock 
  of 
  the 
  fall 
  of 
  such 
  a 
  heavy 
  body." 
  He 
  supposed 
  it 
  to 
  be 
  marine 
  in 
  its 
  

   habits, 
  accustomed 
  to 
  battling 
  a 
  stormy 
  sea. 
  However 
  his 
  objection 
  to 
  leaping 
  on 
  land 
  is 
  

   obviated 
  by 
  our 
  hypothesis 
  of 
  its 
  erect 
  attitude, 
  and 
  its 
  exclusive 
  use 
  of 
  the 
  hinder 
  limbs, 
  

   the 
  weight 
  always 
  falling 
  on 
  the 
  latter. 
  

  

  The 
  disproportion 
  between 
  the 
  fore 
  and 
  hind 
  limbs 
  of 
  the 
  Iguanodon, 
  together 
  with 
  

   the 
  compressed 
  form 
  of 
  the 
  tail 
  suggested 
  to 
  Prof. 
  Owen 
  an 
  aquatic 
  habit, 
  a 
  relation 
  of 
  

   proportions 
  of 
  limbs 
  to 
  habit 
  seen 
  in 
  the 
  tailless 
  Batrachia. 
  The 
  discovery 
  of 
  the 
  massive 
  

   short-toed 
  foot 
  of 
  the 
  Iguanodon 
  subsequently, 
  has 
  lent 
  little 
  countenance 
  to 
  the 
  supposi- 
  

   tion 
  of 
  its 
  entire 
  adaptation 
  to 
  aquatic 
  life. 
  Dr. 
  Leidy 
  has 
  regarded 
  the 
  still 
  greater 
  dis- 
  

   proportion 
  in 
  the 
  case 
  of 
  the 
  Hadrosaurus 
  as 
  an 
  index 
  of 
  a 
  habit 
  like 
  that 
  of 
  the 
  Kanga- 
  

   roos 
  (Macropus, 
  etc.), 
  and 
  that 
  that 
  moster 
  rested 
  in 
  an 
  oblique 
  position 
  on 
  the 
  hind 
  limbs 
  

   and 
  tail, 
  and 
  reached 
  upwards 
  with 
  its 
  muzzle 
  and 
  short 
  fore 
  limbs 
  to 
  the 
  foilage 
  on 
  which 
  

   it 
  fed. 
  He 
  seems 
  also 
  to 
  have 
  regarded 
  it 
  as 
  aquatic 
  as 
  he 
  adds, 
  "on 
  the 
  shores 
  of 
  the 
  

   ocean 
  in 
  which 
  it 
  lived." 
  These 
  genera 
  could 
  not 
  have 
  been 
  aquatic 
  in 
  any 
  great 
  degree, 
  

   as 
  the 
  form 
  of 
  the 
  toes 
  was 
  too 
  stout, 
  and 
  they 
  could 
  have 
  been 
  too 
  little 
  separated 
  to 
  

   allow 
  of 
  a 
  natatory 
  web. 
  

  

  The 
  bulk 
  of 
  the 
  species, 
  as 
  compared 
  with 
  that 
  of 
  Hadrosaurus, 
  illustrates 
  again 
  the 
  

   law 
  observed 
  in 
  the 
  relation 
  between 
  Felis 
  and 
  Bos, 
  and 
  the 
  other 
  raptorial 
  and 
  herbivor- 
  

   ous 
  Dinosauria. 
  

  

  In 
  the 
  same 
  chocolate 
  greensand 
  bed 
  the 
  workmen 
  found 
  a 
  femur 
  of 
  Hadrosaurus 
  

   foulkii, 
  smaller 
  than 
  that 
  described 
  by 
  Dr. 
  Leidy 
  ; 
  also 
  portions 
  of 
  Mosasaurus 
  dekayi. 
  

   Either 
  on 
  the 
  chocolate 
  or 
  in 
  the 
  green 
  stratum 
  above 
  it, 
  remains 
  of 
  Bottosaurus 
  harlani, 
  

   Hyposaurus 
  rogersi 
  Owen, 
  and 
  Holops 
  gavials 
  of 
  perhaps 
  four 
  species, 
  with 
  Cimoliasaurus 
  

   magnus 
  Leidy, 
  were 
  found. 
  

  

  The 
  only 
  molluscs 
  which 
  occurred 
  with 
  the 
  remains 
  of 
  Laelaps 
  were 
  Baculites 
  ovatus 
  

   and 
  Cucullaea 
  vulgaris. 
  Ten 
  feet 
  above 
  is 
  a 
  stratum 
  of 
  Ostrea 
  vesicularis 
  and 
  Terebratula 
  

   harlani 
  

  

  Synonymy. 
  — 
  The 
  only 
  doubt 
  as 
  to 
  the 
  proper 
  name 
  of 
  this 
  genus, 
  has 
  arisen 
  -with 
  reference 
  to 
  the 
  description 
  

   of 
  the 
  genus 
  Dinodon 
  by 
  Leidy. 
  I 
  have 
  eleared 
  this 
  matter 
  up 
  in 
  Silliman's 
  Journal, 
  1868, 
  p. 
  415, 
  as 
  follows 
  : 
  

  

  In 
  the 
  Transactions 
  of 
  the 
  American 
  Philosophical 
  Society, 
  xi. 
  p. 
  143, 
  Dr. 
  Leidy 
  describes 
  a 
  large, 
  carnivorous 
  

   reptile 
  allied 
  to 
  Megalosaurus, 
  under 
  the 
  name 
  of 
  Dinodon 
  Jiorridus. 
  He 
  assigns 
  to 
  it, 
  with 
  some 
  expression 
  of 
  

   doubt, 
  teeth 
  of 
  two 
  distinct 
  forms, 
  viz 
  : 
  some 
  having 
  a 
  lenticular 
  transverse 
  section, 
  with 
  crenation 
  on 
  the 
  two 
  

   margins 
  in 
  part, 
  and 
  others 
  having 
  a 
  lenticular 
  section 
  truncate 
  to 
  a 
  greater 
  or 
  less 
  degree, 
  in 
  place 
  of 
  one 
  of 
  its 
  

   angles, 
  and 
  therefore 
  crenate 
  on 
  three 
  edges 
  in 
  part. 
  

  

  