﻿AND 
  REPTILIA 
  OF 
  NORTH 
  AMERICA. 
  15 
  

  

  EURYTHORAX, 
  Cope. 
  

  

  Established 
  on 
  a 
  large 
  thoracic 
  shield 
  of 
  peculiar 
  form. 
  It 
  is 
  a 
  median, 
  and 
  

   exhibits 
  broad 
  smooth 
  surfaces 
  for 
  the 
  contact 
  of 
  the 
  overlapping 
  margins 
  of 
  the 
  

   lateral 
  plates. 
  The 
  form 
  is 
  subround 
  with 
  a 
  large 
  excavation 
  from 
  the 
  posterior 
  mar- 
  

   gin 
  on 
  each 
  side. 
  The 
  narrowed 
  portion 
  left 
  has 
  a 
  convex 
  outline. 
  Sculpture 
  none. 
  

   The 
  form 
  resembles 
  remotely 
  -the 
  corresponding 
  scute 
  of 
  Tuditanus 
  punctidatus, 
  the 
  

   posterior 
  narrow 
  face 
  representing 
  the 
  xiphisternal 
  process 
  of 
  that 
  species. 
  

  

  EURYTHORAX 
  SUBL^EVIS, 
  Cope. 
  

  

  Proceed. 
  Amer. 
  Philos. 
  Soc, 
  1871, 
  177. 
  

  

  The 
  specific 
  characters 
  expressed 
  by 
  this 
  shield 
  are 
  best 
  perceived 
  in 
  the 
  measurements 
  : 
  

  

  M. 
  

  

  Length, 
  .0715 
  

  

  Greatest 
  width 
  (imperfect), 
  .078 
  

  

  Width 
  of 
  lateral 
  concavity, 
  .039 
  

  

  Some 
  delicate 
  radiating 
  grooves 
  are 
  seen 
  on 
  the 
  exposed 
  surface, 
  but 
  they 
  are 
  very 
  shallow. 
  They 
  are 
  not 
  

   visible 
  on 
  the 
  faces 
  of 
  contact. 
  

  

  This 
  represents 
  one 
  of 
  the 
  largest 
  species 
  of 
  this 
  fauna, 
  having 
  pertained 
  to 
  an 
  animal 
  of 
  probably 
  four 
  feet 
  in 
  

   length, 
  perhaps 
  longer. 
  It 
  will 
  be 
  desirable 
  in 
  future 
  to 
  compare 
  it 
  with 
  the 
  corresponding 
  part 
  of 
  the 
  Tuditanus 
  

   huxleyi, 
  though 
  the 
  latter, 
  so 
  far 
  as 
  known, 
  is 
  the 
  smaller 
  species. 
  

  

  COLOSTEUS, 
  Cope. 
  

   Transac. 
  Amer. 
  Philos. 
  Soc, 
  1869, 
  XIV., 
  p. 
  22. 
  

  

  COLOSTEUS 
  SCTJTELLATUS, 
  dewberry. 
  

  

  Cope, 
  Proceed. 
  Amer. 
  Philos. 
  Soc, 
  1871, 
  p. 
  41. 
  Pygopterus 
  scutellatus, 
  Newberry, 
  Proceed. 
  Acad. 
  Nat. 
  Sci., 
  

   Philadelphia, 
  1856, 
  p. 
  98. 
  Colosteus 
  crassiscutatus, 
  Cope, 
  Transac. 
  Amer. 
  Philos. 
  Soc, 
  XIV., 
  1869, 
  23. 
  

  

  COLOSTEUS 
  FOVEATUS, 
  iJope. 
  

   Transac. 
  Amer. 
  Philos. 
  Soc, 
  1859, 
  XIV., 
  p. 
  24. 
  

  

  COLOSTEUS 
  PAUCIRADIATUS, 
  Cope, 
  Sp. 
  JSTov. 
  

  

  Established 
  on 
  median 
  and 
  lateral 
  pectoral 
  plates 
  of 
  two 
  individuals, 
  the 
  latter 
  of 
  which 
  I 
  formerly 
  referred 
  

   to 
  the 
  C. 
  scutellatus. 
  It 
  belonged 
  to 
  a 
  larger 
  specimen 
  than 
  either 
  of 
  the 
  preceding, 
  and 
  is 
  distinguished 
  by 
  the 
  

   paucity 
  and 
  weakness 
  of 
  its 
  ridges. 
  These 
  are 
  entirely 
  transverse 
  on 
  the 
  posterior 
  third 
  of 
  the 
  length, 
  but 
  are 
  inter- 
  

   rupted 
  and 
  irregular 
  on 
  the 
  median 
  portion 
  ; 
  the 
  anterior 
  third 
  is 
  almost 
  smooth. 
  

  

  The 
  lateral 
  shield 
  is 
  little 
  larger 
  than 
  the 
  largest 
  of 
  C. 
  scutellatus, 
  but 
  resembles 
  the 
  median 
  plate 
  in 
  its 
  low 
  

   and 
  distant 
  carinse. 
  An 
  arc 
  drawn 
  at 
  about 
  the 
  middle 
  of 
  a 
  radial 
  line 
  from 
  the 
  outer 
  angle 
  crosses 
  about 
  eleven 
  of 
  

   these 
  ridges 
  ; 
  in 
  C. 
  scutellatus, 
  twenty 
  in 
  the 
  same 
  space. 
  

  

  The 
  median 
  plate 
  is 
  pyriform 
  with 
  the 
  posterior 
  angle 
  little 
  produced, 
  and 
  the 
  anterior 
  not 
  narrowed 
  and 
  

  

  rather 
  short. 
  The 
  lateral 
  shield 
  is 
  a 
  right 
  angled 
  triangle, 
  the 
  inner 
  or 
  thin 
  edge 
  concave 
  posteriorly, 
  the 
  posterior 
  

  

  convex. 
  

  

  M. 
  

  

  Length 
  of 
  median, 
  0.063 
  

  

  Width 
  " 
  " 
  .040 
  

  

  " 
  lateral 
  behind, 
  .0242 
  

  

  Length 
  of 
  lateral, 
  ."45 
  

  

  