﻿152 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  Lin. 
  

  

  Length 
  of 
  vertebral 
  plate, 
  16.25 
  

   " 
  anterior 
  suture 
  plate, 
  7.5 
  

  

  " 
  " 
  lateral 
  suture 
  plate, 
  7.25 
  

  

  " 
  posterior 
  " 
  " 
  " 
  , 
  11. 
  

  

  " 
  " 
  suture, 
  10. 
  

  

  Diameter 
  of 
  neural 
  canal, 
  2.25 
  

  

  Length 
  of 
  centrum 
  vertebra, 
  No. 
  2, 
  13.75 
  

  

  Width 
  " 
  behind 
  diapophyses, 
  7. 
  

  

  " 
  " 
  at 
  " 
  12. 
  

  

  Depth 
  " 
  with 
  plate, 
  anteriorly, 
  12. 
  

  

  Width 
  of 
  costal 
  plate 
  No. 
  1, 
  17. 
  

   ' 
  ' 
  head 
  of 
  rib 
  on 
  No. 
  1 
  at 
  origin, 
  7. 
  

  

  Width 
  costal 
  plate, 
  No. 
  3, 
  21.25 
  

  

  " 
  " 
  " 
  5, 
  25.5 
  

  

  Thickness 
  of 
  costal 
  plate 
  at 
  28.25 
  lines 
  from 
  prox. 
  suture, 
  4.5 
  

  

  " 
  second 
  plate 
  at 
  rib 
  on 
  outer 
  margin, 
  6.25 
  

  

  " 
  vertebral 
  plate 
  near 
  margin, 
  3.75 
  

  

  The 
  costal 
  plate 
  of 
  Trionyx, 
  mentioned 
  by 
  Leidy 
  (Cretaceous 
  Reptiles, 
  113), 
  from 
  Burlington 
  Co., 
  N. 
  J., 
  proba- 
  

   bly 
  pertains 
  to 
  the 
  same 
  species. 
  Besides 
  the 
  localities 
  above 
  alluded 
  to 
  for 
  the 
  Tr. 
  priscus, 
  Leidy 
  records 
  a 
  probably 
  

   third 
  cretaceous 
  species 
  from 
  the 
  Mississippi. 
  The 
  marine 
  habitat 
  of 
  some 
  of 
  these 
  species 
  becomes 
  quite 
  probable, 
  

   for 
  both 
  individuals 
  and 
  species 
  are 
  perhaps 
  too 
  numerous 
  for 
  all 
  to 
  have 
  wandered 
  from 
  the 
  mouths 
  of 
  rivers. 
  We 
  

   have 
  the 
  airthority 
  of 
  Duchaillu 
  for 
  the 
  statement 
  tbat 
  the 
  Aspidonectes 
  aspilus 
  is 
  found 
  occasionally 
  at 
  sea, 
  outside 
  

   the 
  mouths 
  of 
  the 
  rivers, 
  where 
  it 
  occurs 
  in 
  tropical 
  western 
  Africa. 
  

  

  TRIONYX 
  GITTTATUS. 
  Leidy. 
  

  

  Proc. 
  Acad. 
  Nat. 
  Sci., 
  Phila., 
  1869, 
  p. 
  66. 
  

  

  Tertiary, 
  at 
  Church 
  Buttes, 
  near 
  Fort 
  Bridger, 
  Wyoming 
  Territory, 
  discovered 
  by 
  Dr. 
  F. 
  V. 
  Hayden. 
  

  

  TRIONYX 
  FOVEATUS, 
  Leidy. 
  

   Pr. 
  A. 
  N. 
  S., 
  1860, 
  p. 
  148. 
  

   From 
  the 
  Upper 
  Jurassic 
  Bad 
  Lands 
  of 
  the 
  Judith 
  River, 
  Nebraska. 
  

  

  TRIONYX 
  PENNATUS, 
  Cope. 
  

  

  Pr. 
  A. 
  N. 
  Sci., 
  1869, 
  p. 
  12. 
  

  

  This 
  species 
  is 
  represented 
  by 
  the 
  distal 
  balf 
  or 
  less 
  of 
  a 
  single 
  costal 
  bone. 
  It 
  indicates 
  a 
  large 
  species 
  of 
  size 
  

   similar 
  to 
  the 
  Trionyx-priscus, 
  Leidy, 
  and 
  of 
  a 
  peculiar 
  and 
  handsome 
  style 
  of 
  sculpture. 
  The 
  bone 
  thickens 
  distally, 
  

   and 
  the 
  margin 
  is 
  heavy 
  and 
  truncate, 
  and 
  rises 
  abruptly 
  above 
  the 
  free 
  extremity 
  of 
  the 
  rib 
  proper. 
  The 
  general 
  

   surface 
  is 
  plane; 
  the 
  structure 
  consists 
  of 
  strong 
  sulci, 
  which 
  are 
  as 
  wide 
  as 
  the 
  intervening 
  ribs, 
  which 
  diverge 
  

   slightly 
  outwards 
  on 
  each 
  side 
  of 
  a 
  narrow 
  plane 
  line, 
  which 
  extends 
  on 
  each 
  side 
  along 
  the 
  inter-costal 
  suture. 
  

   Proximally, 
  these 
  grooves 
  are 
  continuous 
  across 
  the 
  costal 
  bone, 
  forming 
  a 
  very 
  open 
  chevron, 
  pointing 
  outwards; 
  

   but 
  they 
  shorten, 
  and 
  are 
  separated 
  by 
  a 
  triangular 
  area 
  of 
  sub-round 
  pits, 
  which 
  are 
  not 
  regular 
  nor 
  corres- 
  

   ponding 
  with 
  the 
  sulci; 
  the 
  latter 
  shorten 
  to 
  the 
  margin 
  of 
  the 
  bone. 
  The 
  diameter 
  of 
  the 
  pit 
  is 
  often 
  smaller 
  

   than 
  that 
  of 
  the 
  sulci. 
  

  

  