﻿AND 
  AYES 
  OF 
  NORTH 
  AMERICA. 
  25 
  

  

  LABYRINTHODONTIA.* 
  

  

  DICTYOCEPHALUS, 
  Leidy. 
  

   DICTYOCEPHALUS 
  ELEGANS, 
  Leidy. 
  

  

  Proc. 
  Ac. 
  Nat. 
  Sci., 
  1856, 
  256, 
  Emmons' 
  Geology 
  Nor. 
  Amer. 
  p 
  59. 
  Tab. 
  

   Triassic 
  Coal 
  Beds, 
  Chatham 
  County, 
  North 
  Carolina. 
  

  

  BAPHETES, 
  Owen. 
  

   BAPHETES 
  PLANICEPS, 
  Owen. 
  

  

  Quart. 
  Journ. 
  Geol. 
  Soc. 
  Loud., 
  X., 
  1853, 
  Tab. 
  (XI 
  notes.) 
  

   Carboniferous 
  Coal 
  Measures 
  of 
  the 
  Joggins, 
  Nova 
  Scotia. 
  

  

  EUPELOR, 
  Cope. 
  

  

  EUPELOR 
  DURTJS, 
  Cope. 
  

  

  Mastodonsaurus 
  durus, 
  Cope. 
  Proc. 
  Acad. 
  Nat. 
  Sci. 
  Philadelphia, 
  1866. 
  249. 
  

  

  A 
  portion 
  of 
  the 
  table 
  of 
  the 
  cranium 
  of 
  a 
  large 
  labyrinthodont 
  accompanied 
  other 
  fragments 
  of 
  the 
  same 
  in 
  a 
  bed 
  

   of 
  hard 
  black 
  shale, 
  according 
  to 
  Wheatley's 
  section 
  of 
  the 
  Trias 
  at 
  Phcenixville, 
  Pa., 
  (in 
  Silliman's 
  Journal 
  Sci. 
  

   Arts, 
  1861, 
  45.) 
  about 
  181 
  feet 
  from 
  the 
  top 
  of 
  the 
  series, 
  while 
  a 
  tooth 
  formerly 
  described 
  with 
  it 
  is 
  from 
  near 
  83 
  

   feet 
  higher, 
  in 
  " 
  the 
  Plant 
  bed." 
  The 
  Belodon 
  comes 
  from 
  the 
  same 
  as 
  the 
  last. 
  

  

  The 
  largest 
  fragment 
  is 
  eight 
  inches 
  long 
  and 
  eight 
  and 
  one-half 
  wide, 
  and 
  is 
  a 
  portion 
  of 
  the 
  table 
  of 
  the 
  

   cranium 
  exhibiting 
  the 
  usual 
  medial 
  depression 
  and 
  embracing 
  portions 
  of 
  the 
  postorbital 
  and 
  parietal 
  bones 
  ; 
  one 
  

   of 
  the 
  former 
  is 
  four 
  inches 
  six 
  lines 
  long 
  ; 
  both 
  are 
  pitted 
  medially 
  (about 
  3i 
  pits 
  in 
  an 
  inch) 
  and 
  marked 
  

   with 
  short 
  coarse 
  sulci 
  posteriorly. 
  The 
  parietals 
  are 
  two 
  inches 
  nine 
  lines 
  wide 
  behind, 
  and 
  four 
  inches 
  wide 
  

   between 
  the 
  anterior 
  parts 
  of 
  the 
  postorbitals. 
  On 
  what 
  is 
  probably 
  the 
  posterior 
  part 
  of 
  the 
  interorbital 
  region 
  

   (a 
  small 
  part 
  of 
  the 
  posterior 
  margin 
  of 
  the 
  left 
  orbit 
  is 
  preserved) 
  commence 
  two 
  smooth, 
  shallow 
  sulci 
  1 
  in. 
  2 
  1. 
  apart, 
  

   which 
  are 
  probably 
  the 
  posterior 
  extremities 
  of 
  the 
  superficial 
  channels 
  of 
  the 
  face 
  of 
  the 
  Labyrinthodonts. 
  Between 
  

   them 
  the 
  surface 
  is 
  pitted 
  (four 
  or 
  five 
  to 
  the 
  inch). 
  The 
  parietal 
  bones 
  are 
  throughout 
  longitudinally 
  sulcate 
  (four 
  

   and 
  one-half 
  to 
  the 
  inch), 
  with 
  obtuse 
  ridges 
  between. 
  The 
  parietal 
  fontanelle 
  was 
  not 
  discoverable, 
  nor 
  could 
  the 
  

   form 
  of 
  the 
  orbits 
  be 
  certainly 
  determined, 
  though 
  they 
  were 
  probably 
  not 
  large. 
  

  

  From 
  the 
  Triassic 
  Red 
  Sandstone 
  near 
  Phcenixville, 
  Chester 
  County, 
  Penna. 
  Discovered 
  by 
  Charles 
  M. 
  

   Wheatley. 
  

  

  Teeth 
  subcylindric, 
  with 
  large 
  pulp 
  cavity 
  at 
  the 
  basis 
  only 
  : 
  external 
  surface 
  without 
  grooves 
  ; 
  dentine 
  divided 
  

   by 
  numerous 
  flat 
  vertical 
  lamina} 
  of 
  a 
  dense 
  substance, 
  probably 
  enamel, 
  which 
  radiate 
  from 
  very 
  near 
  the 
  pulp 
  

   cavity 
  to 
  the 
  external 
  enamel 
  layer. 
  

  

  I 
  have 
  been 
  much 
  puzzled 
  with 
  the 
  teeth 
  which 
  I 
  described 
  (I. 
  c.) 
  in 
  the 
  above 
  language, 
  as 
  typical 
  of 
  this 
  genus. 
  

   Their 
  constitution 
  has 
  been 
  chemically 
  altered, 
  and 
  the 
  section 
  exhibits 
  the 
  radii 
  of 
  a 
  denser 
  material 
  which 
  unites 
  

   at 
  right 
  angles 
  with 
  a 
  sheath 
  of 
  the 
  same 
  substance 
  which 
  envelopes 
  the 
  tooth 
  externally. 
  

  

  The 
  teeth 
  are 
  of 
  various 
  sizes, 
  sometimes 
  two 
  inches 
  long 
  and 
  more 
  slender 
  in 
  proportion 
  to 
  the 
  length 
  than 
  those 
  

   of 
  the 
  Mastodonsaurus 
  jsegeri 
  and 
  salamandroides 
  ; 
  they 
  are 
  cylindrical, 
  gently 
  curved 
  and 
  acuminate 
  without 
  

   external 
  sulci 
  : 
  of 
  the 
  minute 
  sculpture 
  little 
  can 
  be 
  said, 
  but 
  the 
  casts 
  of 
  the 
  surface 
  are 
  smooth. 
  The 
  roots 
  exhibit 
  

   a 
  short 
  conic 
  pulp 
  cavity. 
  In 
  a 
  few 
  weathered 
  sections 
  the 
  denser 
  radii 
  are 
  well 
  displayed. 
  

  

  They 
  are 
  not 
  convolute 
  as 
  in 
  Labyrinthodonts, 
  but 
  perfectly 
  straight 
  and 
  convergent 
  to 
  a 
  minute 
  central 
  vacuity. 
  

   In 
  a 
  tooth 
  four 
  lines 
  in 
  diameter 
  there 
  appear 
  to 
  be 
  five 
  principal 
  radii, 
  which 
  though 
  exceedingly 
  delicate 
  may 
  some- 
  

   times 
  be 
  seen 
  in 
  longitudinally 
  fractured 
  specimens. 
  

  

  *The 
  Centemodon 
  sulcalus 
  Lea 
  which 
  I 
  referred 
  here 
  in 
  my 
  synopsis 
  of 
  Extinct 
  Batrachia, 
  Proceed. 
  Acad. 
  Nat. 
  Sci.. 
  1868, 
  may 
  be 
  placed 
  among 
  the 
  

   Thecodonts. 
  I 
  was 
  induced 
  to 
  place 
  it 
  here 
  by 
  Lea's 
  ascription 
  of 
  sulci 
  and 
  pulp 
  cavity 
  to 
  the 
  tooth, 
  which 
  I 
  did 
  not 
  understand 
  properly. 
  

  

  AMERI. 
  PHILOSO. 
  SOC. 
  — 
  VOL. 
  XIV. 
  7 
  

  

  