﻿AND 
  AYES 
  OF 
  NORTH 
  AMERICA. 
  75 
  

  

  HOLOPS 
  OBSCURUS, 
  Leidy. 
  

  

  Thoracosaurus 
  obscurus, 
  Cope, 
  Geol. 
  Surv. 
  1ST. 
  J., 
  App. 
  C. 
  GroeodUus 
  obscurus, 
  Leidy, 
  Smithson. 
  Contrib., 
  1S65, 
  

   p. 
  115. 
  Tab. 
  II, 
  fig. 
  4. 
  Undetermined 
  crocodile; 
  teeth 
  tab. 
  I, 
  f. 
  7, 
  8, 
  9. 
  

  

  This 
  species 
  was 
  established 
  by 
  Prof. 
  Leidy 
  on 
  vertebrae 
  from 
  Barnesboro, 
  Gloucester 
  Co. 
  and 
  Arneytown, 
  Bur- 
  

   lington 
  Co., 
  New 
  Jersey. 
  I 
  have 
  procured 
  numerous 
  vertebrae 
  from 
  the 
  former 
  locality, 
  which 
  were 
  associated 
  with 
  

   a 
  cranium, 
  which 
  was 
  nearly 
  destroyed 
  before 
  reaching 
  my 
  hands. 
  Enough, 
  however, 
  has 
  been 
  preserved 
  to 
  indicate 
  

   with 
  certainty 
  that 
  it 
  is 
  agavial, 
  and 
  probably 
  of 
  the 
  same 
  genus 
  as 
  that 
  to 
  which 
  Cook's 
  Monmouth 
  County 
  skull 
  

   belonged. 
  Numerous 
  dermal 
  plates 
  were 
  procured 
  at 
  the 
  same 
  time, 
  which 
  however 
  are 
  not 
  more 
  certainly 
  to 
  be 
  

   ascribed 
  to 
  the 
  T. 
  obscurus 
  than 
  to 
  the 
  T. 
  tenebrosus, 
  of 
  which 
  several 
  portions 
  were 
  discovered 
  in 
  the 
  same 
  excav- 
  

   ations. 
  

  

  The 
  vertebrae 
  from 
  Barnesboro 
  in 
  my 
  possession 
  have 
  apparently 
  pertained 
  to 
  two 
  individuals 
  ; 
  two 
  cervicals, 
  a 
  

   second 
  and 
  fifth 
  dorsal, 
  with 
  six 
  other 
  dorsals 
  and 
  lumbars 
  and 
  a 
  caudal, 
  of 
  the 
  one, 
  and 
  a 
  first 
  and 
  fifth 
  dorsal 
  with 
  

   eleven 
  other 
  dorsals 
  and 
  lumbar 
  vertebras, 
  of 
  the 
  other 
  individual. 
  

  

  In 
  addition 
  to 
  these, 
  I 
  have 
  examined 
  two 
  cervicals 
  found 
  with 
  muzzle 
  and 
  long 
  bones 
  at 
  Barnesboro 
  ; 
  a 
  fine 
  

   series 
  of 
  vertebrae 
  and 
  other 
  bones 
  in 
  the 
  Museum 
  of 
  the 
  Academy 
  from 
  near 
  Birmingham 
  ; 
  three 
  fine 
  series 
  in 
  

   possession 
  of 
  Prof. 
  G. 
  H. 
  Cook,f 
  the 
  Mount 
  Holly 
  Lyceum 
  Natural 
  History, 
  and 
  Prof. 
  0. 
  C 
  Marsh 
  of 
  Yale 
  College, 
  

   all 
  from 
  Birmingham 
  ; 
  portions 
  of 
  two 
  individuals 
  in 
  my 
  own 
  collection 
  from 
  the 
  same 
  place, 
  and 
  a 
  set 
  of 
  eight 
  verte- 
  

   bras 
  from 
  Mullica 
  Hill 
  in 
  my 
  possession. 
  Numerous 
  other 
  specimens 
  of 
  this 
  species 
  have 
  fallen 
  under 
  my 
  examination. 
  

   Hence 
  it 
  is 
  obvious 
  that 
  this 
  is 
  the 
  most 
  abundant 
  gavial 
  of 
  the 
  New 
  Jersey 
  Cretaceous. 
  

  

  A 
  series 
  of 
  cervicals 
  from 
  Birmingham 
  is 
  instructive, 
  showing 
  the 
  differences 
  in 
  the 
  characters 
  of 
  the 
  respective 
  

   vertebrae, 
  The 
  axis, 
  which 
  as 
  usual 
  is 
  coossified 
  with 
  part 
  of 
  the 
  body 
  of 
  the 
  atlas 
  thereby 
  much 
  increasing 
  its 
  

   length, 
  has 
  parapophyses 
  represented 
  by 
  two 
  crests 
  directed 
  downwards 
  and 
  separated 
  by 
  a 
  deep 
  longitudinal 
  cavity; 
  

   they 
  are 
  united 
  in 
  front. 
  An 
  obtuse 
  ridge 
  on 
  the 
  side 
  of 
  the 
  centrum 
  separates 
  two 
  longitudinal 
  concavities. 
  The 
  

   third 
  cervical 
  is 
  also 
  deeply 
  concave 
  below, 
  since 
  the 
  parapophyses 
  descend 
  much 
  below 
  the 
  plane 
  of 
  the 
  centrum, 
  

   and 
  are 
  united 
  by 
  an 
  arched 
  connection 
  in 
  front, 
  which 
  is 
  not 
  separated 
  from 
  the 
  rim 
  of 
  the 
  cup. 
  As 
  usual 
  the 
  para- 
  

   popbyses 
  continue 
  to 
  rise, 
  till 
  on 
  the 
  sixth 
  they 
  are 
  a 
  little 
  above 
  the 
  plane 
  of 
  the 
  centrum. 
  They 
  also 
  become 
  more 
  

   posterior, 
  till 
  on 
  the 
  sixth 
  their 
  centre 
  is 
  opposite 
  the 
  middle 
  of 
  the 
  centrum 
  without 
  ball 
  : 
  on 
  the 
  seventh 
  this 
  

   point 
  is 
  behind 
  the 
  middle. 
  The 
  first 
  dorsal 
  is 
  readily 
  distinguished 
  by 
  the 
  small 
  size 
  and 
  posterior 
  direction 
  of 
  the 
  

   articular 
  face 
  of 
  this 
  parapophysis 
  ; 
  its 
  middle 
  is 
  a 
  little 
  below 
  opposite 
  the 
  middle 
  of 
  the 
  cup. 
  On 
  the 
  third 
  dorsal 
  

   the 
  same 
  point 
  is 
  just 
  above 
  opposite 
  the 
  middle 
  of 
  the 
  cup. 
  

  

  On 
  the 
  fourth 
  cervical 
  a 
  trace 
  of 
  median 
  inferior 
  keel 
  exists 
  ; 
  it 
  is 
  quite 
  strong, 
  but 
  thin 
  and 
  concave 
  on 
  the 
  fifth, 
  

   while 
  on 
  the 
  sixth 
  it 
  is 
  thicker, 
  and 
  does 
  not 
  separate 
  deep 
  concavities, 
  but 
  only 
  slightly 
  concave 
  planes. 
  It 
  is 
  still 
  

   more 
  elevated 
  on 
  the 
  seventh, 
  and 
  increases 
  beyond. 
  On 
  the 
  third 
  there 
  is 
  no 
  distinct 
  hypapophysis. 
  On 
  the 
  fourth, 
  

   a 
  transverse 
  elevation 
  on 
  the 
  anterior 
  arch 
  connecting 
  the 
  parapophyses 
  marks 
  it 
  ; 
  on 
  the 
  next 
  it 
  appears 
  in 
  the 
  same 
  

   place 
  as 
  two 
  small 
  longitudinal 
  tubercles 
  with 
  groove 
  between. 
  On 
  the 
  sixth 
  they 
  are 
  similar 
  but 
  stronger. 
  On 
  the 
  

   seventh 
  it 
  is 
  much 
  more 
  elevated, 
  the 
  groove 
  between 
  its 
  halves 
  being 
  now 
  a 
  transverse 
  plane. 
  On 
  the 
  first 
  dorsal 
  it 
  

   is 
  a 
  simple, 
  large 
  process, 
  extending 
  over 
  half 
  the 
  centrum 
  Avith 
  a 
  small 
  knob 
  behind 
  it 
  : 
  on 
  the 
  third 
  it 
  has 
  a 
  longer 
  

   base, 
  but 
  on 
  the 
  second 
  the 
  longest, 
  extending 
  the 
  whole 
  length 
  of 
  the 
  centrum. 
  On 
  the 
  fifth 
  it 
  is 
  thick, 
  with 
  

   rounded 
  edge 
  below, 
  and 
  with 
  a 
  truncate 
  triangular 
  face 
  in 
  front. 
  It 
  is 
  apparent 
  on 
  the 
  eighth, 
  as 
  an 
  obtuse 
  eleva- 
  

   tion 
  in 
  front. 
  

  

  From 
  the 
  fourth 
  posteriorly 
  the 
  characters 
  are 
  drawn 
  from 
  other 
  series, 
  which 
  show 
  many 
  of 
  these 
  vertebrae. 
  

  

  The 
  cups 
  of 
  the 
  third 
  to 
  fifth 
  cervicals 
  look 
  a 
  little 
  more 
  truncate 
  below, 
  owing 
  to 
  the 
  prominence 
  of 
  the 
  trans- 
  

   verse 
  ridge. 
  They 
  are 
  almost 
  perfectly 
  round 
  thence 
  to 
  the 
  second 
  dorsal, 
  where 
  the 
  transverse 
  diameter 
  begins 
  to 
  

   exceed 
  the 
  vertical 
  a 
  little. 
  First 
  on 
  the 
  fifth 
  dorsal 
  the 
  cup 
  assumes 
  some 
  of 
  the 
  narrowed 
  form 
  of 
  the 
  centrum. 
  

  

  The 
  very 
  numerous 
  lumbars 
  present 
  nothing 
  peculiar. 
  As 
  in 
  other 
  species 
  they 
  are 
  more 
  or 
  less 
  striate 
  grooved 
  

   at 
  the 
  bases 
  of 
  the 
  cups 
  and 
  balls. 
  

  

  The 
  series 
  first 
  mentioned 
  as 
  from 
  Barnesboro 
  presents 
  typical 
  characters 
  of 
  the 
  cervical 
  hypapophyses. 
  

  

  t 
  The 
  types 
  of 
  T. 
  obscurus 
  preserved 
  in 
  the 
  museum 
  of 
  Rutgers 
  College 
  have 
  been 
  kindly 
  placed 
  in 
  my 
  hands 
  by 
  John 
  Smock, 
  Asst. 
  State 
  (Jeologist. 
  

  

  