﻿44 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  green 
  sand 
  of 
  New 
  Jersey, 
  described 
  previously 
  in 
  the 
  Proceedings 
  of 
  the 
  Academy 
  of 
  Natural 
  Sciences, 
  but 
  in 
  that 
  

   the 
  large 
  transverse 
  process 
  is 
  cylindrical, 
  while 
  it 
  is 
  compressed 
  cylindroid 
  in 
  the 
  Ark. 
  saurian, 
  and 
  probably 
  the 
  

   latter 
  belongs 
  to 
  a 
  distinct 
  genus, 
  for 
  which 
  the 
  name 
  Brimosauras 
  is 
  proposed. 
  The 
  bones 
  are 
  imbedded 
  in 
  a 
  hard 
  

   limestone 
  with 
  mollusca, 
  and 
  they 
  probably 
  belong 
  to 
  the 
  cretaceous 
  or 
  to 
  the 
  eocene 
  period. 
  One 
  of 
  the 
  most 
  perfect 
  

   of 
  the 
  vertebrae 
  presents 
  the 
  following 
  measurements: 
  

  

  Inches. 
  

   Length 
  of 
  the 
  body, 
  3^ 
  

  

  Depth 
  articular 
  surfaces, 
  5 
  

  

  Breadth 
  do. 
  do., 
  6 
  

  

  Length 
  of 
  the 
  neural 
  arch, 
  3 
  

  

  Dr. 
  Leidy 
  proposes 
  to 
  consider 
  this 
  species 
  as 
  the 
  type 
  of 
  a 
  genus 
  distinct 
  from 
  the 
  present, 
  because 
  its 
  diapophyses 
  

   are 
  compressed 
  in 
  section, 
  while 
  those 
  of 
  Cimoliasaurus 
  are 
  cylindroid. 
  I 
  think 
  this 
  difference 
  depends 
  on 
  the 
  posi- 
  

   tion 
  in 
  the 
  vertebral 
  column. 
  These 
  processes 
  descend 
  on 
  the 
  anterior 
  part 
  of 
  the 
  column 
  and 
  become 
  more 
  flattened, 
  

   until 
  they 
  resemble 
  diapophyses 
  of 
  ordinary 
  cervicals. 
  This 
  vertebra 
  therefore 
  was 
  an 
  anterior 
  dorsal. 
  

  

  ELASMOSAURUS, 
  Cope. 
  

  

  Leconte's 
  notes 
  on 
  Geology 
  of 
  the 
  route 
  of 
  the 
  Union 
  Pacific 
  Railroad, 
  18G8, 
  p. 
  68. 
  Cope, 
  Proceed. 
  Acad. 
  Nat. 
  

   Sciences, 
  1868, 
  p. 
  92. 
  

  

  This 
  genus 
  has 
  been 
  more 
  completely 
  preserved 
  to 
  us 
  than 
  any 
  other 
  American 
  repre- 
  

   sentative 
  of 
  the 
  order, 
  and 
  hence 
  may 
  be 
  accepted 
  as 
  most 
  clearly 
  expressive 
  of 
  its 
  char- 
  

   acters. 
  In 
  the 
  interpretation 
  of 
  these, 
  however, 
  considerable 
  difficulty 
  has 
  been 
  experi- 
  

   enced, 
  as 
  the 
  structure 
  form 
  appears, 
  at 
  first 
  sight, 
  to 
  reverse 
  to 
  a 
  remarkable 
  degree, 
  

   the 
  usual 
  proportions 
  of 
  known 
  reptiles. 
  

  

  The 
  determination 
  of 
  the 
  anterior 
  extremity 
  of 
  the 
  vertebral 
  column 
  has 
  been 
  rendered 
  

   certain 
  by 
  the 
  fortunate 
  completeness 
  of 
  the 
  cervical 
  series, 
  as 
  the 
  extraordinary 
  length 
  

   of 
  the 
  latter, 
  equalling 
  three 
  times 
  that 
  of 
  the 
  body, 
  renders 
  the 
  most 
  careful 
  scrutiny 
  

   necessary. 
  

  

  The 
  neural 
  arches 
  are 
  every 
  where 
  continuous 
  with 
  the 
  centra, 
  without 
  sign 
  of 
  suture, 
  

   and 
  are 
  externally 
  plane. 
  The 
  neural 
  canal 
  is 
  exceedingly 
  small 
  for 
  the 
  size 
  of 
  the 
  

   vertebrae, 
  especially 
  on 
  the 
  lumbars 
  and 
  caudals. 
  

  

  The 
  dorsal 
  vertebras 
  are 
  remarkable 
  from 
  the 
  fact 
  that 
  the 
  diapophyses 
  disappear 
  on 
  

   the 
  anterior 
  part 
  of 
  the 
  series, 
  and 
  gradually 
  diminish 
  in 
  length 
  from 
  behind 
  forwards 
  to 
  

   the 
  point 
  of 
  disappearance. 
  On 
  the 
  median 
  and 
  posterior 
  parts 
  of 
  the 
  series 
  they 
  are 
  

   very 
  elongate, 
  and 
  rise 
  for 
  a 
  short 
  distance 
  from 
  the 
  basis 
  of 
  the 
  neural 
  arch. 
  Ante- 
  

   riorly, 
  they 
  descend 
  and 
  shorten, 
  and 
  finally 
  remain 
  only 
  as 
  the 
  slightly 
  elevated 
  borders 
  

   of 
  rib-pits. 
  Throughout 
  the 
  whole 
  of 
  the 
  anterior 
  portion 
  of 
  the 
  column 
  to 
  the 
  cervicals, 
  

   the 
  neural 
  spines 
  are 
  of 
  great 
  elevation, 
  and 
  of 
  such 
  antero-posterior 
  extent 
  as 
  to 
  be 
  

   nearly 
  continuous. 
  

  

  The 
  cervical 
  vertebrae 
  are 
  not 
  only 
  more 
  numerous, 
  but 
  become 
  anteriorly 
  much 
  smal- 
  

   ler 
  and 
  more 
  attenuated 
  than 
  in 
  its 
  allies 
  of 
  the 
  same 
  family. 
  They 
  are 
  remarkably 
  com- 
  

  

  