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  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  COLOSTEUS 
  FOVEATUS, 
  Cope. 
  

  

  A 
  very 
  elegant 
  sculptured 
  median 
  pectoral 
  plate 
  represents 
  this 
  Batrachian. 
  It 
  is 
  larger 
  than 
  most 
  of 
  

   those 
  of 
  C. 
  radiatus, 
  but 
  smaller 
  than 
  the 
  one 
  last 
  described. 
  The 
  posterior 
  and 
  median 
  parts 
  of 
  the 
  plate 
  

   are 
  pitted 
  to 
  the 
  number 
  of 
  six 
  in 
  five 
  mm. 
  The 
  pits 
  are 
  separated 
  by 
  sharply 
  defined 
  ridges. 
  They 
  elongate 
  

   towards 
  the 
  anterior 
  parts 
  of 
  the 
  plate, 
  resembling 
  elongate 
  hexagons, 
  and 
  the 
  ridges 
  approaching 
  radii, 
  though 
  

   not 
  more 
  elevated 
  than 
  the 
  cross 
  septa. 
  The 
  bevelled 
  margins 
  are 
  rugose 
  also, 
  except 
  at 
  the 
  edges. 
  

  

  M. 
  

  

  Length 
  of 
  the 
  bone, 
  ,045 
  

  

  Greatest 
  width, 
  .025 
  

  

  Width 
  posterior 
  margin, 
  .021 
  

  

  From 
  Linton, 
  Columbiana 
  County, 
  Ohio. 
  Prof. 
  J. 
  S. 
  Newberry, 
  Coll. 
  No. 
  20. 
  

  

  COLOSTEUS 
  MARSHII, 
  Cope. 
  

  

  Sp. 
  nov. 
  

  

  This 
  species 
  is 
  represented 
  by 
  a 
  specimen 
  of 
  very 
  much 
  smaller 
  size 
  than 
  either 
  of 
  the 
  preceding. 
  That 
  it 
  is 
  not 
  

   the 
  young 
  of 
  C. 
  crassiscutatus 
  is 
  indicated 
  by 
  the 
  peculiar 
  form 
  of 
  the 
  dermal 
  ventral 
  scales, 
  and 
  by 
  the 
  greater 
  

   anterior 
  prolongation 
  of 
  the 
  median 
  ventral 
  dermal 
  bone. 
  

  

  The 
  specimen 
  is 
  lying 
  on 
  its 
  back, 
  displaying 
  the 
  ventral 
  armature 
  somewhat 
  disturbed, 
  and 
  broken 
  through 
  in 
  

   some 
  places, 
  where 
  the 
  vertebrae 
  and 
  ribs 
  would 
  be 
  discerned 
  if 
  they 
  existed. 
  The 
  head 
  is 
  turned 
  abruptly 
  to 
  one 
  

   side, 
  and 
  is 
  apparently 
  right 
  side 
  up. 
  Several 
  of 
  its 
  elements 
  are 
  scattered 
  on 
  adjacent 
  portions 
  of 
  the 
  block. 
  

  

  The 
  head 
  is 
  of 
  an 
  elongate 
  lanceolate 
  form. 
  The 
  upper 
  surface 
  of 
  the 
  frontal 
  bones 
  is 
  punctate-rugose 
  in 
  relief, 
  

   with 
  short 
  radii 
  towards 
  the 
  margin. 
  The 
  distal 
  two-thirds 
  of 
  the 
  mandible 
  is 
  narrow 
  wedge-shaped 
  ; 
  the 
  external 
  

   surface 
  is 
  coarsely 
  pitted. 
  There 
  are 
  ho 
  teeth 
  preserved. 
  The 
  sutures 
  of 
  the 
  cranial 
  hones 
  are 
  of 
  the 
  squamosal 
  tj 
  pe 
  

   or 
  fish-like. 
  

  

  The 
  three 
  thoracic 
  shields 
  are 
  considerably 
  displaced. 
  The 
  lateral 
  are 
  subtriangular, 
  and 
  are 
  strongly 
  ridged 
  

   towards 
  the 
  inner 
  margin. 
  The 
  median 
  shield 
  is 
  short 
  spatulate, 
  the 
  narrow 
  portion 
  directed 
  anteriorly 
  ; 
  the 
  posterior 
  

   rounded. 
  It 
  is 
  coarsely 
  pitted 
  medially, 
  and 
  coarsely 
  and 
  strongly 
  radiate 
  ridged 
  to 
  the 
  margin. 
  Immediately 
  behind 
  

   these 
  plates 
  the 
  dermal 
  armature 
  commences. 
  It 
  consists 
  of 
  elongate, 
  narrow, 
  subcylindric 
  scales, 
  which 
  are 
  arranged 
  

   end 
  to 
  end, 
  in 
  series 
  which 
  meet 
  on 
  the 
  median 
  line, 
  converging 
  anteriorly, 
  as 
  in 
  the 
  other 
  types 
  here 
  described. 
  At 
  

   first 
  sight 
  they 
  resemble 
  the 
  long 
  rod-like 
  pieces 
  of 
  (Estoeephalus, 
  and 
  careful 
  examination 
  is 
  needed 
  to 
  detect 
  the 
  

   interruptions 
  caused 
  by 
  the 
  sutures 
  of 
  the 
  scales. 
  The 
  latter 
  are 
  several 
  times 
  as 
  long 
  as 
  wide, 
  and 
  appear 
  to 
  be 
  

   terminated 
  by 
  oblique 
  faces 
  as 
  in 
  the 
  typical 
  species. 
  

  

  The 
  trace 
  of 
  limbs 
  is 
  only 
  seen 
  in 
  a 
  short 
  impression 
  resembling 
  that 
  of 
  a 
  humerus 
  behind 
  the 
  thoracic 
  buckler. 
  

   Nothing 
  can 
  be 
  found 
  pertaining 
  to 
  posterior 
  limbs, 
  but 
  some 
  laminae 
  and 
  impressions 
  in 
  the 
  position 
  of 
  pelvis, 
  but 
  

   not 
  immediately 
  connected 
  with 
  the 
  other 
  portions 
  of 
  the 
  skeleton, 
  may 
  belong 
  to 
  the 
  latter 
  arch. 
  

  

  Measurement 
  a. 
  MM. 
  

  

  Length 
  of 
  body 
  to 
  buckler, 
  4.2 
  

  

  Width 
  of 
  ventral 
  armature, 
  .8 
  

  

  Impression 
  of 
  humerus, 
  (or 
  coracoid,) 
  .2 
  

  

  Length 
  median 
  thoracic 
  plate, 
  1-15 
  

  

  Width 
  " 
  " 
  " 
  ,51 
  

  

  Length 
  fragment 
  under 
  jaw, 
  .75 
  

  

  Depth 
  do. 
  at 
  middle, 
  .15 
  

  

  Width 
  end 
  muzzle, 
  .29 
  

  

  This 
  species, 
  like 
  the 
  preceding, 
  is 
  from 
  Dr. 
  Newberry's 
  collection, 
  (No. 
  13,) 
  and 
  from 
  the 
  Linton 
  coal 
  bed, 
  South- 
  

   eastern 
  Ohio. 
  I 
  have 
  dedicated 
  it 
  to 
  Prof. 
  Othniel 
  C. 
  Marsh. 
  Professor 
  of 
  Palaeontology 
  in 
  Yale 
  College, 
  Connecticut. 
  

  

  