﻿54 
  

  

  THE 
  EXTINCT 
  BATRACHIA, 
  REFTILIA 
  

  

  Fig. 
  

  

  Fig. 
  12. 
  

  

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  19 
  

  

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  sometimes 
  cylhidric, 
  and 
  som 
  times 
  narrowed. 
  The 
  surface 
  from 
  a 
  short 
  distance 
  above 
  the 
  alveolar 
  margins 
  to 
  the 
  

   tip, 
  is 
  marked 
  with 
  acute 
  thread-like 
  ridges, 
  which 
  are 
  sometimes 
  interrupted, 
  and 
  some- 
  

   times 
  furnished 
  with 
  short 
  branchlets. 
  They 
  are 
  more 
  or 
  less 
  undulate, 
  and 
  do 
  not 
  unite, 
  

   hut 
  simply 
  cease 
  as 
  the 
  tip 
  of 
  the 
  tooth 
  is 
  approached. 
  The 
  latter 
  is 
  smooth 
  without 
  lateral 
  

   cutting 
  edges. 
  The 
  width 
  of 
  the 
  mandible 
  at 
  the 
  commencement 
  of 
  the 
  rami 
  is 
  3 
  in. 
  .05 
  

   lin.; 
  of 
  the 
  muzzle 
  of 
  the 
  seventh 
  tooth 
  3 
  in. 
  7.5 
  lin.; 
  at 
  the 
  third 
  tooth 
  2 
  in. 
  4.2 
  lin. 
  

  

  General 
  Be 
  narks. 
  — 
  The 
  tail 
  is 
  a 
  powerful 
  swimming 
  organ, 
  more 
  or 
  less 
  compressed 
  in 
  

   life, 
  hence 
  the 
  specific 
  name, 
  which 
  means 
  flat-tailed. 
  

  

  The 
  dinger 
  of 
  injury 
  to 
  which 
  such 
  an 
  excessively 
  elongate 
  neck 
  has 
  been 
  exposed, 
  would 
  

   render 
  the 
  recovery 
  of 
  a 
  perfect 
  specimen 
  like 
  the 
  present, 
  an 
  unusual 
  chance. 
  The 
  neural 
  

   spines 
  of 
  the 
  dorsal 
  region 
  are 
  so 
  elevated 
  and 
  closely 
  placed 
  as 
  to 
  allow 
  of 
  little 
  or 
  no 
  vertical 
  

   motion 
  of 
  the 
  column 
  downwards, 
  while 
  those 
  of 
  the 
  cervical 
  and 
  caudal 
  region 
  being 
  nar- 
  

   rower, 
  the 
  elevation 
  of 
  the 
  head 
  is 
  quite 
  possible, 
  and 
  an 
  upward 
  flexure 
  easy. 
  

  

  The 
  habit 
  of 
  this 
  species, 
  like 
  that 
  of 
  its 
  nearest 
  known 
  allies, 
  was 
  raptorial, 
  as 
  evinced 
  

   by 
  the 
  numerous 
  canine-like 
  teeth, 
  and 
  the 
  fish 
  remains 
  taken 
  from 
  beneath 
  its 
  vertebrae. 
  

  

  The 
  general 
  form 
  of 
  this 
  reptile, 
  whether 
  it 
  was 
  furnished 
  with 
  large 
  posterior 
  limbs 
  or 
  

   not, 
  was 
  that 
  of 
  a 
  serpent 
  with 
  a 
  relatively 
  shorter, 
  more 
  robust 
  and 
  more 
  posteriorly 
  placed 
  

   body 
  than 
  is 
  characteristic 
  of 
  true 
  serpents, 
  and 
  with 
  two 
  pairs 
  of 
  limbs 
  or 
  paddles. 
  It 
  pro- 
  

   gressed 
  by 
  the 
  strokes 
  of 
  its 
  paddles, 
  assisted 
  by 
  its 
  powerful 
  and 
  oar-like 
  tail. 
  The 
  body 
  

   was 
  steadied 
  by 
  the 
  elevated 
  keel 
  of 
  the 
  median 
  dorsal 
  line, 
  formed 
  by 
  the 
  broad, 
  high 
  neural 
  

   spines. 
  The 
  snake-like 
  neck 
  was 
  raised 
  high 
  in 
  the 
  air, 
  or 
  depressed 
  at 
  the 
  will 
  of 
  the 
  animal, 
  

   now 
  arched 
  swan-like 
  preparatory 
  to 
  a 
  plunge 
  after 
  a 
  fish, 
  now 
  stretched 
  in 
  repose 
  on 
  the 
  

   water 
  or 
  deflexed 
  in 
  exploring 
  the 
  depths 
  below. 
  

  

  Differences 
  from 
  other 
  Sauropterygia. 
  — 
  The 
  only 
  genus 
  with 
  which 
  it 
  is 
  necessary 
  to 
  com- 
  

   pare 
  this 
  present 
  one 
  is 
  Cimoliasaurus. 
  The 
  following 
  may 
  be 
  noted 
  as 
  generic 
  distinctions: 
  The 
  

   series 
  of 
  cervicals 
  rapidly 
  diminishes 
  in 
  Cimoliasaurus 
  in 
  absolute 
  size 
  and 
  in 
  relative 
  length 
  of 
  the 
  vertebras, 
  

   which 
  are 
  not 
  compressed. 
  In 
  the 
  present 
  genus 
  they 
  maintain 
  a 
  similar 
  length 
  for 
  a 
  considerable 
  distance, 
  

   diminish 
  in 
  length 
  very 
  gradually 
  and 
  are 
  much 
  compressed. 
  The 
  diapophyses 
  of 
  the 
  dorsal 
  vertebra?, 
  

   as 
  they 
  descend, 
  in 
  Cimoliasaurus, 
  continue 
  well 
  developed 
  until 
  they 
  attain 
  the 
  inferior 
  planes 
  of 
  the 
  

   centrum, 
  and 
  have 
  there 
  a 
  downward 
  direction. 
  In 
  Elasmosaurus 
  they 
  cease 
  while 
  yet 
  on 
  the 
  middle 
  of 
  

   the 
  centrum, 
  and 
  are 
  replaced 
  by 
  pits 
  throughout 
  the 
  remainder 
  of 
  the 
  length. 
  

  

  The 
  neural 
  canal 
  is 
  everywhere 
  markedly 
  larger 
  in 
  Cimoliasaurus. 
  

  

  As 
  the 
  characters 
  of 
  lesser 
  significance 
  may 
  be 
  added, 
  that 
  in 
  Cimoliasaurus 
  magnus 
  the 
  dorsals 
  

   with 
  elevated 
  diapophyses 
  are 
  considerably 
  larger 
  in 
  the 
  centra 
  than 
  those 
  in 
  which 
  they 
  are 
  situated 
  

   lower 
  down. 
  In 
  E. 
  platyurus 
  these 
  vertebrae 
  are 
  of 
  relatively 
  equal 
  length. 
  

  

  The 
  cervical 
  pleurapophyses 
  in 
  C. 
  magnus 
  are 
  anteriorly 
  considerably 
  stouter 
  and 
  less 
  flattened: 
  the 
  

   same 
  applies 
  to 
  more 
  anterior 
  vertebras, 
  where 
  they 
  are 
  flatter 
  in 
  both. 
  

  

  In 
  comparing 
  this 
  species 
  with 
  the 
  Cimoliasaurus 
  grandis, 
  Leidy, 
  from 
  Arkansas, 
  we 
  observe 
  first 
  

   the 
  generic 
  character 
  of 
  the 
  strong 
  inferior 
  diapophyses 
  in 
  the 
  latter. 
  That 
  species 
  marks 
  itself 
  also 
  

   as 
  a 
  preeminently 
  short-necked 
  form, 
  as 
  these 
  anterior 
  dorsals 
  are 
  even 
  shorter 
  than 
  in 
  C. 
  magnus, 
  belli"- 
  nearly 
  twice 
  

   as 
  wide 
  as 
  long. 
  The 
  depth 
  of 
  the 
  articular 
  faces 
  is 
  also 
  relatively 
  greater 
  than 
  in 
  the 
  E. 
  platyurus. 
  

  

  History. 
  — 
  The 
  determination 
  of 
  the 
  extremities 
  of 
  this 
  species 
  was 
  rendered 
  difficult 
  from 
  the 
  fact 
  that 
  Leidy 
  in 
  

   his 
  descriptions 
  of 
  Cimoliasaurus, 
  reverses 
  the 
  relations 
  of 
  the 
  vertebra', 
  viewing 
  the 
  cervicals 
  as 
  caudals 
  and 
  lum- 
  

   bars, 
  and 
  describing 
  the 
  caudals 
  as 
  belonging 
  to 
  another 
  genus. 
  Not 
  suspecting 
  this 
  error, 
  I 
  arranged 
  the 
  skeleton 
  of 
  

   Elasmosaurus 
  with 
  the 
  same 
  relation 
  of 
  extremities, 
  and 
  the 
  more 
  willingly 
  as 
  the 
  distal 
  cervicals 
  present 
  an 
  extraor- 
  

   dinary 
  attenuation, 
  even 
  for 
  this 
  type, 
  and 
  also 
  as 
  the 
  discoverer 
  assured 
  me 
  that 
  the 
  fragments 
  of 
  cranium 
  were 
  

   found 
  at 
  the 
  extremity 
  which 
  is 
  properly 
  the 
  caudal. 
  Viewed 
  in 
  this 
  light 
  many 
  details 
  of 
  the 
  structure 
  were 
  the 
  re- 
  

  

  

  

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