﻿90 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  Lengtli 
  ft. 
  

  

  Poly 
  acanthus, 
  Owen, 
  9 
  

  

  Scelidosaurus 
  harrisonii, 
  Owen, 
  12 
  

  

  Iguanodon 
  anglicus, 
  Meyer, 
  28 
  

  

  Hylaeosaurus 
  armatus, 
  Mant, 
  21 
  

  

  Hadrosaurus 
  foulkei, 
  Leidy, 
  28 
  

  

  Poecilopleurum 
  bucklandii, 
  Deslong, 
  25* 
  

  

  * 
  

  

  Megalosaurus 
  bucklandii, 
  Mant, 
  1 
  30 
  

  

  Laelaps 
  aquilunguis, 
  Cope, 
  21 
  

  

  Teratosaurus 
  suevicus, 
  Meyer, 
  1 
  30 
  

  

  Ornithotarsus 
  immanis, 
  Cope, 
  ? 
  35 
  

  

  Prof. 
  Owen 
  suspects 
  the 
  animals 
  of 
  this 
  order 
  to 
  have 
  had 
  the 
  septum 
  of 
  the 
  ventricles 
  

  

  of 
  the 
  heart 
  complete 
  as 
  in 
  the 
  Crocodilia. 
  It 
  is 
  an 
  interesting 
  inquiry 
  whether 
  there 
  were 
  

  

  two 
  aorta-roots 
  or 
  only 
  one, 
  and 
  if 
  one, 
  whether 
  the 
  right 
  or 
  left 
  remained. 
  I 
  have 
  little 
  

  

  doubt 
  that 
  the 
  Dinosauria 
  further 
  resembled 
  Crocodilia 
  in 
  having 
  the 
  lateral 
  lobes 
  of 
  the 
  

  

  cerebellum 
  developed, 
  and 
  the 
  vermis 
  plicate. 
  

  

  The 
  affinity 
  to 
  the 
  modern 
  Sauria, 
  or 
  Lacertilia, 
  which 
  some 
  authors 
  have 
  allowed 
  of, 
  

   is 
  very 
  slight 
  ; 
  the 
  Crocodilia, 
  though 
  somewhat 
  removed, 
  are 
  the 
  nearest 
  living 
  allies. 
  If 
  

   we 
  consent 
  to 
  a 
  derivative 
  relation 
  between 
  types, 
  we 
  must 
  consider 
  this 
  order 
  to 
  have 
  given 
  

   origin 
  by 
  divergence 
  and 
  metamorphosis 
  to 
  both 
  the 
  Mammalia 
  and 
  Aves. 
  The 
  structure 
  

   and 
  embryology 
  of 
  the 
  last 
  two 
  classes 
  forbid 
  the 
  idea 
  that 
  either 
  could 
  have 
  been 
  derived 
  

   from 
  the 
  other. 
  

  

  Besides 
  the 
  differences 
  in 
  the 
  structure 
  of 
  the 
  tarsus 
  and 
  metatarsus 
  observed 
  in 
  this 
  

   order, 
  there 
  are 
  marked 
  differences 
  in 
  that 
  of 
  the 
  tibia. 
  Thus 
  most 
  of 
  the 
  order 
  present 
  a 
  

   very 
  prominent 
  spine 
  and 
  crest, 
  of 
  bird-like 
  character 
  ; 
  but 
  Plateosaurus 
  Meyer 
  and 
  Tera- 
  

   tosaurus 
  Meyer 
  both 
  Triassic 
  genera, 
  appear 
  to 
  possess 
  this 
  character 
  in 
  a 
  very 
  slight 
  

   degree, 
  the 
  former 
  scarcely 
  at 
  all. 
  I 
  have, 
  therefore, 
  not 
  included 
  them 
  in 
  the 
  groups 
  

   following. 
  

  

  ORTHOPODA. 
  

  

  Cope 
  Prcc. 
  Acad. 
  PMla., 
  1860, 
  317. 
  Therosauria 
  Ilacckel, 
  18G3. 
  

  

  Proximal 
  tarsal 
  bones 
  distinct 
  from 
  each 
  other 
  and 
  from 
  the 
  tibia, 
  articulating 
  with 
  a 
  

   tibia 
  and 
  with 
  a 
  terminal 
  face 
  of 
  a 
  well 
  developed 
  fibula. 
  The 
  ilium 
  with 
  a 
  massive 
  

   narrowed 
  anterior 
  prolongation. 
  

  

  In 
  the 
  few 
  genera 
  of 
  this 
  suborder, 
  of 
  which 
  the 
  teeth 
  have 
  been 
  discovered, 
  a 
  successive 
  

   divergence 
  from 
  the 
  type 
  of 
  the 
  Goniopoda 
  is 
  visible, 
  in 
  the 
  shortening 
  and 
  increase 
  in 
  

  

  * 
  These 
  estimates 
  I 
  have 
  reason 
  to 
  think 
  exaggerated. 
  

  

  