﻿In. 
  

  

  Lin. 
  

  

  33 
  

  

  6. 
  

  

  14 
  

  

  9. 
  

  

  6 
  

  

  9. 
  

  

  7 
  

  

  3. 
  

  

  27 
  

  

  

  16 
  

  

  

  7 
  

  

  6. 
  

  

  52 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  portion, 
  which 
  extends 
  across 
  behind 
  the 
  precoracoid 
  foramina; 
  a 
  strong 
  elevated 
  rib 
  extends 
  across 
  the 
  posterior 
  face 
  

   at 
  this 
  point. 
  The 
  outer 
  margin 
  of 
  the 
  coracoid 
  is 
  thickened, 
  rounded 
  and 
  slightly 
  concave. 
  

  

  Greatest 
  antero-posterior 
  length 
  scapular 
  arch, 
  

  

  " 
  " 
  " 
  clavicle, 
  

  

  " 
  " 
  " 
  glenoid 
  cavity, 
  

  

  " 
  " 
  " 
  precoracoid 
  foramen, 
  

  

  Transverse 
  extent 
  of 
  claviculi, 
  

  

  " 
  " 
  coracoidea, 
  

  

  From 
  acetabulum 
  to 
  foramen, 
  

  

  The 
  form 
  of 
  the 
  posterior 
  margin 
  of 
  the 
  coracoidea 
  is 
  unknown, 
  and 
  they 
  are 
  much 
  broken 
  on 
  the 
  inner 
  margin. 
  

   They 
  may 
  have 
  been 
  considerably 
  longer 
  than 
  in 
  the 
  accompanying 
  cut. 
  

  

  The 
  greater 
  part 
  of 
  the 
  pelvic 
  arch 
  appears 
  to 
  be 
  preserved. 
  From 
  the 
  obliquity 
  of 
  the 
  median 
  suture 
  and 
  

   from 
  the 
  form 
  of 
  the 
  pubes 
  as 
  they 
  are 
  preserved 
  on 
  a 
  large 
  nodule 
  of 
  indurated 
  clay, 
  it 
  is 
  evident 
  that 
  they 
  have 
  

   formed 
  a 
  boat-shaped 
  support 
  to 
  the 
  abdominal 
  viscera, 
  with 
  an 
  obtuse 
  keel 
  on 
  the 
  median 
  line 
  below. 
  The 
  following 
  

   diagram 
  will 
  explain 
  the 
  relation 
  of 
  its 
  parts. 
  

  

  In. 
  Lin. 
  

  

  Greatest 
  antero-posterior 
  length, 
  25 
  

  

  " 
  " 
  " 
  pubis, 
  

  

  Antero-posterior 
  median 
  length 
  to 
  notch 
  of 
  ischia. 
  

   Length 
  coracoids 
  behind 
  notch, 
  

   Greatest 
  width 
  pubes, 
  

  

  " 
  " 
  ischia, 
  

  

  The 
  anterior 
  and 
  lateral 
  portions 
  of 
  the 
  pubes 
  are 
  very 
  thin, 
  as 
  are 
  also 
  the 
  median 
  posterior 
  portions 
  of 
  the 
  

   ischiadic 
  plates. 
  The 
  pubic 
  bones 
  are 
  thickest 
  on 
  the 
  posterior 
  margin; 
  they 
  present 
  a 
  downward 
  projecting 
  median 
  

   convexity 
  near 
  the 
  anterior 
  end. 
  Depth 
  of 
  the 
  articular 
  face, 
  2 
  in., 
  8 
  lin. 
  

  

  The 
  superior 
  surface 
  of 
  this 
  arch 
  was 
  brought 
  to 
  light 
  by 
  the 
  exertions 
  of 
  my 
  friends, 
  B. 
  Waterhouse 
  Hawkins 
  and 
  

   Wm. 
  M. 
  Gabb, 
  who 
  removed 
  a 
  large 
  mass 
  of 
  matrix 
  which 
  fortunately 
  accompanied 
  and 
  protected 
  it. 
  This 
  presents 
  

   a 
  transverse 
  thickening 
  extending 
  across 
  it, 
  and 
  continuous 
  with 
  the 
  posterior 
  margin 
  of 
  the 
  clavicles. 
  A 
  median 
  

   longitudinal 
  thickening 
  extends 
  from 
  this 
  to 
  the 
  anterior 
  emargination, 
  embracing 
  in 
  its 
  angle 
  with 
  the 
  transverse, 
  

   a 
  shallow 
  concavity. 
  The 
  posterior 
  projection 
  which 
  is 
  continuous 
  with 
  the 
  median 
  part 
  of 
  the 
  ischia, 
  is 
  strongly 
  de- 
  

   Hexed 
  behind 
  the 
  transverse 
  rib, 
  and 
  is 
  continuous 
  with 
  the 
  basin-like 
  concavity 
  formed 
  by 
  the 
  united 
  pubes. 
  The 
  

   glenoid 
  surface 
  of 
  the 
  pubes 
  is 
  a 
  sigmoid, 
  while 
  that 
  of 
  the 
  ischia 
  is 
  regularly 
  convex. 
  The 
  articulation 
  of 
  the 
  ilium 
  

   has 
  been 
  exclusively 
  with 
  the 
  former. 
  

  

  Of 
  the 
  pleurapophysial 
  portion 
  of 
  the 
  two 
  arches 
  nothing 
  appears 
  to 
  be 
  preserved 
  except 
  two 
  lateral 
  symmetrical 
  

   long 
  bones. 
  One 
  was 
  found 
  imbedded 
  in 
  the 
  mass 
  carrying 
  the 
  pelvic 
  arch, 
  and 
  they 
  articulate 
  well 
  with 
  the 
  pubes; 
  

   but 
  the 
  articular 
  extremity 
  is 
  too 
  short 
  to 
  articulate 
  with 
  ischia 
  at 
  the 
  same 
  time. 
  Though 
  they 
  resemble 
  the 
  inferior 
  

   view 
  of 
  the 
  procoracoids, 
  they 
  represent 
  the 
  ilia 
  of 
  Plesiosaurus. 
  The 
  head 
  is 
  subdiscoid, 
  rather 
  flat, 
  slightly 
  pro- 
  

   jecting 
  excentrically 
  with 
  a 
  ligamentous 
  pit. 
  The 
  articular 
  surface 
  is 
  very 
  oblique 
  to 
  the 
  axis 
  of 
  the 
  shaft, 
  and 
  is 
  

   separated 
  from 
  the 
  surface 
  by 
  a 
  marked 
  angle 
  all 
  around. 
  Nothing 
  like 
  a 
  trochanteric 
  ridge 
  is 
  apparent 
  in 
  this 
  bone. 
  

  

  Length 
  in 
  middle 
  of 
  curve. 
  

   Diameter 
  at 
  head, 
  

  

  " 
  distally 
  on 
  curve. 
  

  

  " 
  " 
  straight. 
  

  

  13 
  

  

  6. 
  

  

  7 
  

  

  

  4 
  

  

  6. 
  

  

  27 
  

  

  6. 
  

  

  21 
  

  

  

  In. 
  

  

  Lin 
  

  

  9 
  

  

  9 
  

  

  3 
  

  

  3 
  

  

  6 
  

  

  

  4 
  

  

  

  