﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  13 
  

  

  posteriorly 
  as 
  the 
  anterior 
  margin 
  of 
  the 
  orbits. 
  The 
  external 
  nostrils 
  are 
  large 
  and 
  opposite 
  the 
  inner 
  margin 
  of 
  

   the 
  orbit 
  on 
  each 
  side. 
  This 
  separation 
  of 
  the 
  nares 
  is 
  associated 
  with 
  a 
  greater 
  transverse 
  extent 
  of 
  the 
  premaxil- 
  

   laries 
  than 
  in 
  some 
  of 
  the 
  genera. 
  These 
  have 
  been 
  set 
  with 
  numerous 
  teeth, 
  judging 
  by 
  their 
  small 
  impressions 
  ; 
  

   no 
  larger 
  ones 
  have 
  left 
  traces, 
  and 
  no 
  traces 
  of 
  any 
  on 
  the 
  maxillaries. 
  The 
  teeth 
  of 
  the 
  genera 
  before 
  described 
  

   are 
  all 
  much 
  larger 
  relatively, 
  indicating 
  still 
  farther 
  the 
  diversity 
  between 
  them. 
  

  

  A 
  fragment 
  of 
  mandible 
  remains, 
  but 
  without 
  teeth 
  or 
  external 
  surface. 
  It 
  shows 
  a 
  large 
  internal 
  canal. 
  

  

  Measurements. 
  Lines. 
  

  

  Total 
  length 
  cranium, 
  25 
  .5 
  

  

  Width 
  do. 
  three 
  lines 
  behind 
  orbits, 
  24 
  

   Do. 
  between 
  orbits, 
  7.5 
  

  

  Do. 
  do. 
  nares, 
  5 
  

  

  Do. 
  occipital 
  condyles, 
  2.2 
  

  

  Do. 
  of 
  supraoccipital 
  bones, 
  6 
  

  

  Do. 
  of 
  right 
  parietal, 
  G 
  

  

  Extent 
  of 
  premaxillaries, 
  8.7 
  

  

  Length 
  orbit, 
  6 
  

  

  From 
  the 
  Coal 
  Measures 
  at 
  Linton, 
  Columbiana 
  county, 
  Ohio. 
  Discovered 
  by 
  Dr. 
  

   Jno. 
  S. 
  Newberry. 
  When 
  the 
  remainder 
  of 
  the 
  skeleton 
  of 
  this 
  species 
  is 
  known, 
  its 
  

   generic 
  relations 
  will 
  be 
  better 
  established. 
  

  

  Another 
  cranium 
  accompanies 
  the 
  collection, 
  which 
  belongs 
  to 
  a 
  species 
  distinct 
  from 
  

   the 
  last. 
  The 
  muzzle 
  is 
  not 
  so 
  broadly 
  rounded 
  and 
  the 
  premaxillary 
  teeth 
  are 
  relative- 
  

   ly 
  much 
  larger. 
  The 
  sculpture 
  is 
  more 
  delicate 
  with 
  the 
  ridges 
  more 
  acute. 
  The 
  orbits 
  

   and 
  nares 
  are 
  not 
  defined. 
  The 
  maxillary 
  is 
  well 
  preserved 
  for 
  a 
  length 
  of 
  an 
  inch 
  ; 
  its 
  

   teeth 
  are 
  smaller 
  than 
  the 
  premaxilliries 
  ; 
  I 
  count 
  four 
  in 
  a 
  line 
  ; 
  crown 
  simple 
  conic. 
  

   External 
  surface 
  of 
  maxillary 
  not 
  very 
  strongly 
  sculptured. 
  

  

  This 
  species 
  cannot 
  be 
  referred 
  to 
  its 
  genus 
  without 
  further 
  material. 
  I 
  therefore 
  do 
  

   not 
  name 
  it. 
  

  

  DENDRERPETON 
  ACADIANUM, 
  Owen. 
  

  

  Quart. 
  Joum. 
  Geol. 
  Soc. 
  X., 
  1853, 
  81. 
  Dawson, 
  Loc. 
  Cit. 
  

   Coal 
  Measures. 
  Joggins, 
  of 
  Nova 
  Scotia. 
  

  

  DENDRERPETON 
  OWENII, 
  Dawson. 
  

  

  Canadian 
  Naturalist 
  and 
  Geologist, 
  VIII., 
  161. 
  

   Coal 
  Measures 
  : 
  as 
  the 
  last. 
  

  

  HYLERPETON, 
  Owen. 
  

  

  HYLERPETON 
  DAWSONI, 
  Owen. 
  

  

  Journ. 
  Geol. 
  Loc. 
  Lond. 
  Loc. 
  Cit. 
  Dawson, 
  Canadian 
  Naturalist 
  and 
  Geologist, 
  VIII., 
  272. 
  

   Carboniferous 
  Coal 
  Measures. 
  The 
  Joggins, 
  Nova 
  Scotia. 
  

   AMERI. 
  PHILOSO. 
  SOC. 
  — 
  VOL. 
  XIV. 
  4 
  

  

  