﻿80 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  Several 
  individuals 
  of 
  this, 
  the 
  largest 
  of 
  our 
  cretaceous 
  species, 
  have 
  been 
  found, 
  but 
  only 
  fragments 
  preserved. 
  

   The 
  cranial 
  bones 
  are 
  smoother 
  than 
  those 
  of 
  the 
  species 
  of 
  Holops, 
  and 
  the 
  posterior 
  nares 
  are 
  separated 
  as 
  above 
  

   mentioned. 
  The 
  cervical 
  vertebrae 
  of 
  this 
  species 
  are 
  distinguished 
  among 
  those 
  of 
  its 
  congeners 
  by 
  the 
  lack 
  of 
  

   inferior 
  concavity, 
  breadth 
  of 
  basal 
  carina, 
  complete 
  bifurcation 
  of 
  low 
  hypapophyses, 
  and 
  posterior 
  and 
  transverse 
  

   position 
  of 
  parapophyses. 
  

  

  AMPHICOELIA. 
  

  

  HYPOSAURUS, 
  Owen. 
  

   Journ. 
  Geol. 
  Soc, 
  London, 
  V., 
  383. 
  

  

  This 
  genus 
  is 
  as 
  yet 
  the 
  only 
  known 
  representative 
  on 
  this 
  continent 
  of 
  the 
  Amphi- 
  

   coelian 
  Crocodiles. 
  It 
  belongs, 
  says 
  Owen, 
  to 
  the 
  Teleosauriclae, 
  from 
  which 
  the 
  great 
  

   size 
  of 
  the 
  parapophysis 
  distinguishes 
  it. 
  Its 
  remains 
  are 
  quite 
  abundant 
  in 
  the 
  New 
  

   Jersey 
  cretaceous 
  ; 
  stratigraphically 
  its 
  position 
  is 
  the 
  latest 
  of 
  its 
  family. 
  Thoraco- 
  

   saurus 
  being 
  the 
  earliest 
  of 
  the 
  Procoelian 
  Crocodilia, 
  the 
  interesting 
  spectacle 
  is 
  pre- 
  

   sented 
  of 
  the 
  coexistence 
  in 
  America 
  in 
  large 
  numbers, 
  of 
  two 
  types 
  which, 
  in 
  the 
  old 
  

   world, 
  are 
  separated 
  by 
  the 
  whole 
  period 
  between 
  the 
  Jurassic 
  and 
  Tertiary. 
  

  

  As 
  might 
  be 
  supposed 
  then, 
  there 
  is 
  some 
  approximation 
  in 
  structure 
  between 
  these 
  

   two 
  extreme 
  genera 
  of 
  their 
  series. 
  The 
  hypapophyses 
  of 
  the 
  cervical 
  vertebra 
  in 
  Thor- 
  

   acosaurus 
  are 
  of 
  the 
  Teleosauroid 
  type. 
  Both 
  are 
  alike 
  slender-nosed 
  genera, 
  as 
  I 
  have 
  

   been 
  able 
  to 
  asc3rtain 
  for 
  the 
  first 
  time 
  for 
  some 
  of 
  them. 
  

  

  As 
  a 
  Teleosaurian 
  reptile 
  the 
  bassioccipital 
  does 
  not 
  present 
  the 
  vertical 
  position 
  usual 
  

   among 
  the 
  Procoeli, 
  but 
  is 
  horizontal. 
  The 
  sphenoid 
  is 
  also 
  more 
  horizontal 
  in 
  its 
  expo- 
  

   sure, 
  and 
  much 
  wider, 
  and 
  with 
  a 
  straight 
  anterior 
  margin, 
  not 
  incised 
  to 
  accommodate 
  

   the 
  posterior 
  nares. 
  The 
  frontal 
  bone 
  is 
  marked 
  with 
  longitudinal 
  shallow 
  grooves. 
  

  

  The 
  teeth 
  of 
  Hyposaurus 
  are 
  more 
  compressed 
  than 
  in 
  the 
  last 
  genus 
  described, 
  some 
  

   of 
  them 
  are 
  from 
  the 
  shortening 
  of 
  the 
  crown 
  almost 
  triangular 
  in 
  outline, 
  but 
  most 
  are 
  

   elongate 
  ; 
  the 
  enamel 
  is 
  thrown 
  into 
  a 
  few 
  fine 
  continuous 
  ridges. 
  

  

  The 
  cervicals 
  may 
  be 
  distinguished 
  from 
  those 
  of 
  the 
  other 
  gavials 
  of 
  New 
  Jersey, 
  in 
  

   addition 
  to 
  the 
  form 
  of 
  the 
  articular 
  faces, 
  by 
  the 
  earlier 
  appearance 
  of 
  a 
  strong 
  keel-like 
  

   hypapophysis, 
  that 
  is, 
  on 
  the 
  fourth 
  of 
  the 
  series 
  ; 
  at 
  first 
  it 
  is 
  most 
  prominent 
  at 
  the 
  

   anterior 
  end. 
  

  

  HYPOSAURUS 
  ROGERSII, 
  Oiren. 
  

  

  Loc. 
  Cit. 
  Leidy, 
  Cretaceous 
  Reptile 
  N. 
  Am., 
  p. 
  18, 
  Tab. 
  Ill, 
  4-21. 
  

  

  Vertebra. 
  — 
  The 
  neural 
  spines 
  of 
  the 
  cervical 
  vertebr.-e 
  are 
  acuminate, 
  of 
  considerable 
  — 
  finally, 
  of 
  great— 
  height, 
  

   the 
  anterior 
  standing 
  transversely 
  on 
  the 
  neural 
  arch, 
  the 
  median 
  subtetragonal, 
  the 
  posterior, 
  as 
  usual, 
  

   longitudinal 
  in 
  section. 
  In 
  an 
  anterior 
  cervical 
  vertebra, 
  length 
  2 
  in., 
  the 
  spine 
  is 
  2 
  in. 
  10 
  1. 
  above 
  the 
  ceiling 
  of 
  

   the 
  arch, 
  and 
  is 
  acute 
  ; 
  it 
  receives 
  a 
  strong 
  lateral 
  wing 
  from 
  each 
  posterior 
  zygapophysis, 
  which 
  does 
  not 
  disappear 
  

   till 
  near 
  the 
  tip. 
  These 
  enclose 
  a 
  deep 
  groove 
  on 
  each 
  side 
  behind, 
  with 
  a 
  strictly 
  perpendicular 
  posterior 
  median 
  

  

  