﻿PROM 
  THE 
  KEtTPER 
  SANDSTONE 
  OP 
  WARWICK. 
  431 
  

  

  is 
  compared 
  to 
  " 
  a 
  smaller 
  foramen 
  in 
  the 
  corresponding 
  part 
  of 
  the 
  

   smooth 
  orbital 
  plate 
  in 
  the 
  anterior 
  frontal 
  of 
  the 
  crocodile." 
  But 
  

   it 
  is 
  the 
  lachrymal, 
  not 
  the 
  prefrontal, 
  which, 
  in 
  the 
  Crocodilia, 
  is 
  

   thus 
  excavated. 
  The 
  prefrontal 
  of 
  Mastodonsaurus, 
  to 
  which 
  genus 
  

   the 
  present 
  bone 
  might 
  conjecturally 
  be 
  referred 
  on 
  account 
  of 
  its 
  

   proportions 
  and 
  surface-ornament, 
  has 
  been 
  shown, 
  in 
  the 
  earlier 
  

   part 
  of 
  this 
  paper, 
  to 
  have 
  a 
  thin, 
  bevelled 
  orbital 
  margin. 
  I 
  have 
  

   little 
  doubt 
  that 
  the 
  supposed 
  anterior 
  frontal 
  belongs 
  to 
  the 
  occipital 
  

   tract, 
  and 
  that 
  the 
  pit 
  represents 
  a 
  foramen 
  for 
  the 
  passage 
  of 
  a 
  

   large 
  vessel, 
  perhaps 
  the 
  carotid 
  artery. 
  In 
  Capitosaurus 
  such 
  fora- 
  

   mina 
  upon 
  the 
  occipital 
  surface 
  are 
  clearly 
  seen*. 
  The 
  bone 
  cannot, 
  

   as 
  yet, 
  be 
  accurately 
  identified 
  with 
  Mastodonsaurus 
  pachygnaihus, 
  

   to 
  which 
  species, 
  however, 
  it 
  may 
  be 
  provisionally 
  referred. 
  

  

  Plate 
  44. 
  figs. 
  8, 
  9. 
  Labyrinthodon 
  leptognaihus, 
  Owen. 
  

  

  The 
  mandibles, 
  so 
  determined 
  by 
  Professor 
  Owen, 
  may 
  well 
  have 
  

   belonged 
  to 
  the 
  cranial 
  fragment 
  which 
  furnishes 
  the 
  type 
  of 
  the 
  

   genus 
  and 
  species. 
  The 
  teeth 
  have 
  not, 
  I 
  believe, 
  been 
  microscopic- 
  

   ally 
  compared. 
  

  

  Plate 
  43. 
  figs. 
  4-11 
  ; 
  Plate 
  44. 
  figs. 
  1-3. 
  Labyrinthodon 
  'pachygna- 
  

   ihus, 
  Owen. 
  

  

  In 
  the 
  preceding 
  part 
  of 
  this 
  paper 
  reasons 
  have 
  been 
  given 
  for 
  

   the 
  belief 
  in 
  a 
  smaller 
  species 
  of 
  Mastodonsaurus, 
  for 
  which 
  the 
  name 
  

   of 
  pachygnaihus 
  may 
  be 
  retained. 
  Tbe 
  two 
  species 
  differ 
  in 
  size, 
  in 
  

   the 
  proportion 
  of 
  the 
  orbit 
  to 
  the 
  interorbital 
  space, 
  in 
  the 
  form 
  of 
  

   the 
  auditory 
  fossa, 
  and 
  in 
  the 
  character 
  of 
  the 
  external 
  surface 
  of 
  

   the 
  mandibular 
  ramus. 
  As 
  is 
  the 
  case 
  with 
  nearly 
  all 
  the 
  Warwick 
  

   Labyrinthodonts, 
  the 
  remains 
  are 
  so 
  fragmentary 
  as 
  to 
  preclude 
  an 
  

   entirely 
  satisfactory 
  definition 
  of 
  the 
  species. 
  There 
  seems 
  reason 
  

   for 
  including 
  under 
  one 
  name 
  all 
  the 
  fossils 
  here 
  enumerated. 
  

  

  Plate 
  45. 
  

  

  Of 
  the 
  seven 
  objects 
  'represented 
  in 
  this 
  plate 
  there 
  is 
  probably 
  

   not 
  one 
  which 
  belongs 
  to 
  a 
  Labyrinthodont. 
  Certainly 
  not 
  one 
  of 
  

   them 
  can 
  be 
  identified 
  with 
  any 
  part 
  of 
  an 
  indubitable 
  Labyrintho- 
  

   dont 
  specimen. 
  The 
  vertebrae 
  (figs. 
  1-8) 
  are 
  too 
  elongate 
  in 
  the 
  

   antero-posterior 
  direction, 
  and 
  they 
  want 
  the 
  neuro-central 
  suture. 
  

   The 
  " 
  episternum" 
  (figs. 
  9, 
  10) 
  has 
  no 
  resemblance 
  to 
  any 
  ossification 
  

   in 
  the 
  Labyrinthodont 
  skeleton. 
  The 
  ilium 
  (figs. 
  16, 
  17) 
  is 
  probably 
  

   reptilian. 
  Of 
  the 
  head 
  of 
  the 
  femur 
  (fig. 
  18) 
  I 
  can 
  say 
  nothing, 
  

   except 
  that 
  it 
  is 
  too 
  globose 
  for 
  the 
  articular 
  end 
  of 
  any 
  of 
  the 
  bones 
  

   of 
  the 
  extremities 
  of 
  the 
  well-established 
  genera 
  in 
  this 
  order. 
  The 
  

   criticisms 
  offered 
  by 
  Von 
  Meyer 
  f 
  and 
  by 
  Prof. 
  Huxley 
  J 
  should 
  be 
  

   attentively 
  considered 
  by 
  all 
  who 
  would 
  study, 
  in 
  detail, 
  Prof. 
  Owen's 
  

   Memoir 
  or 
  the 
  Warwick 
  Collection. 
  

  

  * 
  Quenstedt, 
  Mastodonsaurier 
  &c, 
  t. 
  iii. 
  fig„ 
  16. 
  

  

  + 
  Palaontologie 
  Wiirttembergs, 
  p. 
  36. 
  

  

  X 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xxri. 
  p. 
  47. 
  

  

  