﻿AVD 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  17 
  

  

  ly 
  on 
  the 
  median 
  line. 
  Limbs 
  distinctly 
  developed. 
  Ribs 
  long, 
  well 
  developed. 
  Scales 
  

   none. 
  

  

  In 
  more 
  detail, 
  we 
  have 
  an 
  elongate 
  lanceolate 
  head 
  with 
  little 
  or 
  no 
  sculpture 
  of 
  the 
  

   external 
  surface 
  of 
  the 
  bones. 
  The 
  angles 
  of 
  the 
  mandibles 
  are 
  much 
  prolonged 
  

   backwards 
  as 
  in 
  Apateon 
  and 
  frogs, 
  and 
  the 
  well 
  developed 
  ribs 
  commence 
  but 
  a 
  short 
  

   distance 
  behind 
  the 
  head. 
  The 
  vertebrae 
  are 
  slender, 
  and 
  furnished 
  with 
  well 
  developed 
  

   diapophyses. 
  

  

  The 
  neural 
  spines 
  of 
  dorsal 
  vertebras 
  in 
  O. 
  remex 
  are 
  flattened 
  and 
  expanded 
  in 
  the 
  

   line 
  of 
  the 
  vertebral 
  column, 
  and 
  weakly 
  grooved 
  to 
  their 
  superior 
  margin. 
  Their 
  char- 
  

   acter 
  has 
  not 
  been 
  observed 
  in 
  the 
  other 
  species. 
  

  

  The 
  neural 
  and 
  haemal 
  spines 
  of 
  the 
  caudal 
  vertebrae 
  are 
  prolonged, 
  and 
  remarkably 
  

   sculptured 
  by 
  longitudinal 
  grooves, 
  which 
  are 
  most 
  distinct 
  towards 
  their 
  terminations. 
  

   They 
  are 
  much 
  flattened 
  to 
  support 
  an 
  oar-like 
  tail. 
  

  

  Anterior 
  limbs 
  have 
  been 
  seen 
  in 
  two 
  species, 
  and 
  posterior 
  in 
  one 
  other. 
  Though 
  

   they 
  all 
  probably 
  possess 
  two 
  pairs 
  of 
  limbs, 
  this 
  point 
  is 
  not 
  entirely 
  established, 
  leaving 
  

   the 
  homogeneity 
  of 
  this 
  genus 
  still 
  somewhat 
  uncertain. 
  

  

  A 
  pair 
  of 
  symmetrical 
  bones 
  whose 
  impressions 
  are 
  seen 
  posterior 
  to 
  the 
  occipital 
  bone 
  

   appear 
  to 
  be 
  the 
  coracoid, 
  and 
  one 
  of 
  them 
  is 
  followed 
  by 
  a 
  second 
  element, 
  which 
  is 
  

   probably 
  the 
  humerus. 
  A 
  third 
  piece 
  follows, 
  which 
  is 
  ulna, 
  or 
  radius; 
  the 
  second 
  bone 
  

   of 
  the 
  forearm 
  is 
  lost, 
  but 
  some 
  impressions, 
  which 
  appear 
  to 
  be 
  those 
  of 
  a 
  digit, 
  are 
  

   visible. 
  

  

  The 
  skin 
  has 
  been 
  occupied 
  by 
  a 
  great 
  number 
  of 
  closely 
  packed, 
  curved, 
  spine- 
  

   shaped 
  scales. 
  They 
  have 
  occupied 
  the 
  ventral 
  integument, 
  passing 
  from 
  the 
  median 
  line 
  

   of 
  the 
  belly 
  outwards 
  and 
  posteriorly, 
  having 
  acute 
  tips 
  which 
  may 
  or 
  not 
  have 
  penetrated 
  

   the 
  skin 
  on 
  each 
  side. 
  No 
  such 
  tegumentary 
  spines 
  protected 
  the 
  dorsal 
  region. 
  

  

  The 
  three 
  sculptured 
  dermothoracic 
  plates 
  common 
  to 
  so 
  many 
  of 
  this 
  order, 
  have 
  not 
  

   been 
  seen 
  in 
  this 
  genus. 
  

  

  As 
  compared 
  with 
  Sauropleura, 
  this 
  genus 
  is 
  more 
  elongate 
  and 
  snake-like, 
  and 
  with 
  

   much 
  weaker 
  limbs; 
  these 
  characters 
  are 
  not 
  sufficient 
  to 
  distinguish 
  it 
  alone, 
  but 
  as 
  no 
  

   dilated 
  neural 
  spines 
  nor 
  similar 
  abdominal 
  armature 
  are 
  discoverable 
  in 
  the 
  former, 
  I 
  

   prefer 
  to 
  keep 
  them 
  separate 
  for 
  the 
  present. 
  

  

  OESTOCEPHALUS 
  REMEX, 
  Cope. 
  

  

  Sauropleura 
  remex, 
  Cope. 
  Pi-oc. 
  Ac. 
  Nat. 
  Sci., 
  Philada., 
  1868, 
  p. 
  217. 
  OestorepMlux 
  amphiuminvs, 
  Cope, 
  

   1. 
  c. 
  p. 
  218. 
  

  

  Additional 
  specimens 
  received 
  from 
  Dr. 
  Newberry 
  enable 
  me 
  to 
  combine 
  the 
  caudal 
  

   vertebrae 
  described 
  as 
  above 
  under 
  the 
  genus 
  Sauropleura, 
  with 
  the 
  remainder 
  of 
  the 
  skel- 
  

  

  AMEBI. 
  PHILOSO. 
  SOO. 
  — 
  VOL. 
  XIV. 
  5 
  

  

  