﻿46 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  it 
  would 
  suggest 
  the 
  existence 
  of 
  a 
  fore 
  limb, 
  of 
  comparatively 
  little 
  power, 
  though 
  no 
  

   remains 
  of 
  such 
  have 
  been 
  found. 
  The 
  acetabulum 
  is 
  smaller 
  than 
  the 
  glenoid 
  cavity 
  ; 
  

   this 
  point, 
  with 
  the 
  obvious 
  source 
  of 
  propulsive 
  power 
  in 
  the 
  tail, 
  renders 
  it 
  probable 
  that 
  

   the 
  posterior 
  limbs 
  were 
  the 
  weaker 
  of 
  the 
  two, 
  if 
  any 
  existed. 
  But 
  there 
  is 
  no 
  trace 
  of 
  

   sacrum 
  nor 
  of 
  any 
  modified 
  diapophyses 
  for 
  support 
  of 
  an 
  ilium. 
  

  

  The 
  ischia 
  are 
  flat, 
  subtriangular 
  bones 
  with 
  a 
  long 
  median 
  line 
  of 
  junction, 
  and 
  

   communicating 
  anteriorly 
  with 
  the 
  posterior 
  prolongation 
  of 
  the 
  pubic 
  plate. 
  Their 
  

   postero-exterior 
  margins 
  project 
  well 
  backwards. 
  The 
  pubes 
  are 
  broad 
  plates, 
  whose 
  

   anterior 
  margins 
  diverge 
  from 
  each 
  other. 
  They 
  are 
  broader 
  than 
  the 
  ischia, 
  and 
  form 
  a 
  

   broad 
  shallow 
  basin 
  for 
  the 
  support 
  of 
  the 
  viscera. 
  The 
  suture 
  defining 
  these 
  elements 
  

   is 
  obliterated 
  ; 
  they 
  are 
  continuous, 
  and 
  form 
  a 
  weak 
  inferior 
  keel 
  on 
  the 
  median 
  bine. 
  

   A 
  simple 
  curved 
  ilium 
  has 
  been 
  preserved, 
  for 
  which 
  there 
  appears 
  to 
  be 
  a 
  smooth 
  articu- 
  

   lar 
  surface 
  on 
  the 
  pubis 
  to 
  which 
  it 
  was 
  attached. 
  

  

  The 
  acetabular 
  portions 
  of 
  these 
  elements 
  are 
  flattened 
  and 
  furnished 
  with 
  convex 
  

   articular 
  surfaces. 
  The 
  supposed 
  ilia 
  are 
  short 
  curved 
  bones, 
  resembling 
  that 
  of 
  Plesio- 
  

   saurus 
  latispinus 
  Ow., 
  or 
  of 
  some 
  of 
  the 
  other 
  species 
  of 
  that 
  family. 
  The 
  shank 
  is 
  flattened 
  

   cylindric, 
  the 
  distal 
  extremity, 
  dilated 
  rounded 
  and 
  flattened. 
  The 
  proximal 
  extremity 
  

   sub-truncate, 
  or 
  truncate 
  in 
  two 
  or 
  three 
  unequal 
  planes, 
  and 
  with 
  a 
  median 
  pit. 
  It 
  fits 
  

   well 
  when 
  applied 
  to 
  a 
  concavity 
  on 
  the 
  articular 
  surface 
  of 
  the 
  pubis. 
  The 
  vertebrae 
  

   above 
  the 
  pelvic 
  arch 
  were 
  furnished 
  with 
  elongate, 
  sub-cylindric 
  diapophyses. 
  

  

  The 
  question 
  as 
  to 
  the 
  presence 
  of 
  posterior 
  limbs 
  remains 
  unsolved. 
  Dr. 
  Turner 
  

   having 
  made 
  a 
  second 
  careful 
  search, 
  and 
  renewed 
  excavations 
  at 
  the 
  original 
  locality, 
  

   failed 
  to 
  find 
  any 
  bones 
  which 
  can 
  be 
  assigned 
  to 
  humerus, 
  ulna, 
  radius, 
  carpus 
  or 
  phalanges, 
  

   or 
  similar 
  elements 
  of 
  the 
  hind 
  limbs. 
  This 
  is 
  the 
  more 
  remarkable, 
  as 
  the 
  pelvic 
  and 
  

   scapular 
  arches 
  were 
  further 
  completed, 
  and 
  an 
  additional 
  number 
  of 
  ribs 
  obtained. 
  The 
  

   inferior 
  and 
  lateral 
  regions 
  of 
  the 
  trunk, 
  being 
  then 
  so 
  abundantly 
  discovered, 
  what 
  are 
  

   we 
  to 
  think 
  of 
  the 
  entire 
  absence 
  of 
  the 
  usually 
  numerous 
  elements 
  of 
  extremities] 
  The 
  

   glenoid 
  cavity 
  is 
  a 
  rather 
  angular 
  cavity, 
  and 
  both 
  were 
  filled 
  with 
  solid 
  argillaceous 
  

   matrix. 
  The 
  acetabula 
  are 
  not 
  cup-like, 
  but 
  merely 
  exposures 
  of 
  the 
  marrow, 
  plane 
  ex- 
  

   tremities 
  of 
  the 
  pubes 
  and 
  ischia 
  ; 
  they 
  were 
  covered 
  with 
  thin 
  layers 
  of 
  gypsum 
  ; 
  the 
  

   pieces 
  of 
  the 
  ilia 
  were 
  found 
  imbedded 
  in 
  the 
  mass 
  of 
  matrix 
  which 
  occupied 
  the 
  pel- 
  

   vic 
  arch. 
  

  

  The 
  allied 
  genus 
  Cimoliasaurus 
  Leidy 
  possesses 
  a 
  femur, 
  as 
  described 
  under 
  head 
  of 
  

   that 
  genus 
  ; 
  it 
  is 
  of 
  shorter 
  and 
  thicker 
  form 
  than 
  in 
  most 
  Plesiosauri. 
  

  

  The 
  skeleton 
  so 
  nearly 
  complete 
  would 
  indicate 
  no 
  violent 
  disturbance 
  of 
  the 
  carcass 
  ; 
  

   but 
  if 
  there 
  were, 
  it 
  would 
  be 
  an 
  unusual 
  accident 
  that 
  all 
  of 
  the 
  four 
  limbs 
  should 
  have 
  

   been 
  removed 
  from 
  their 
  sockets, 
  Avithout 
  leaving 
  even 
  fragments. 
  

  

  