﻿18 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  eton 
  which 
  was 
  the 
  type 
  of 
  the 
  present 
  genus. 
  The 
  species 
  thus 
  constituted 
  is 
  

   represented 
  by 
  five 
  specimens 
  and 
  their 
  reverses, 
  and 
  a 
  fifth 
  may 
  be 
  added 
  with 
  much 
  

   probability. 
  

  

  They 
  indicate 
  an 
  animal 
  of 
  the 
  average 
  size 
  of 
  the 
  Amphiuma 
  means. 
  

  

  The 
  extremities 
  of 
  the 
  vertebra? 
  are 
  deeply 
  concave, 
  but 
  the 
  centra 
  are 
  so 
  long 
  as 
  to 
  prevent 
  the 
  concavities 
  en- 
  

   tering 
  more 
  than 
  one-fifth 
  of 
  the 
  latter, 
  each. 
  The 
  diapophyses 
  are 
  behind 
  the 
  middle, 
  and 
  are 
  broad, 
  curved 
  back- 
  

   wards, 
  and 
  acuminate 
  as 
  in 
  Amphiuma. 
  The 
  centra 
  have 
  a 
  prominent 
  median 
  line 
  below, 
  with 
  a 
  longitudinal 
  con- 
  

   cavity 
  on 
  each 
  side. 
  Five 
  of 
  them 
  a 
  little 
  exceed 
  an 
  inch 
  in 
  length. 
  Neural 
  spines 
  moderate. 
  The 
  hu- 
  

   merus 
  is 
  longer 
  than 
  the 
  coracoid, 
  and 
  is 
  considerably 
  dilated 
  distally 
  ; 
  the 
  coracoid 
  slightly 
  dilated 
  at 
  its 
  superior 
  

   extremity. 
  The 
  dermal 
  armature 
  commences 
  immediately 
  behind 
  the 
  head, 
  and 
  forms 
  a 
  band 
  of 
  14 
  lines 
  in 
  width 
  ; 
  

   measuring 
  across 
  the 
  spine-like 
  scales, 
  in 
  a 
  width 
  of 
  a 
  line, 
  four 
  cylinders 
  may 
  be 
  counted. 
  The 
  external 
  portions 
  

   are 
  curved 
  backwards, 
  the 
  interior 
  nearly 
  straight, 
  those 
  of 
  the 
  anterior 
  series 
  more 
  delicate 
  than 
  the 
  posterior. 
  

  

  The 
  head 
  is 
  wedge-shaped, 
  with 
  regularly 
  acuminate 
  sides. 
  The 
  top 
  of 
  the 
  cranium 
  is 
  somewhat 
  broken 
  in 
  the 
  

   specimen 
  ; 
  the 
  portions 
  preserved 
  are 
  smooth, 
  and 
  the 
  longitudinal 
  suture 
  is 
  distinct 
  for 
  a 
  considerable 
  distance. 
  

   The 
  angle 
  of 
  the 
  mandible 
  is 
  produced 
  considerably 
  behind 
  the 
  occiput, 
  and 
  is 
  enlarged 
  and 
  rounded. 
  The 
  end 
  of 
  

   the 
  muzzle 
  is 
  broken 
  away, 
  and 
  the 
  region 
  of 
  the 
  orbits 
  so 
  fractured 
  as 
  to 
  render 
  their 
  precise 
  location 
  uncertain. 
  

   The 
  superficial 
  layer 
  of 
  the 
  cranial 
  bones 
  is 
  nowhere 
  clearly 
  visible, 
  so 
  that 
  it 
  cannot 
  be 
  ascertained 
  whether 
  it 
  is 
  

   sculptured 
  or 
  not. 
  The 
  quadrate 
  bone 
  projects 
  well 
  posteriorly. 
  Some 
  fragments 
  indicate 
  small 
  cylindric 
  teeth, 
  as 
  

   in 
  Amphibamus, 
  but 
  they 
  are 
  not 
  characteristic. 
  

  

  Measurements. 
  Lines. 
  

  

  Length 
  cranium 
  without 
  muzzle, 
  17.3 
  

  

  Width 
  do 
  posteriorly, 
  11.5 
  

  

  Length 
  of 
  the 
  coracoid, 
  2.1 
  

  

  Length 
  humerus, 
  2.5 
  

  

  Length 
  of 
  sixth 
  vertebra 
  from 
  skull, 
  3 
  

  

  Extent 
  diapophyses, 
  3.5 
  

  

  Width 
  centrum, 
  1.5 
  

  

  The 
  characters 
  of 
  the 
  genus 
  are 
  further 
  shown 
  by 
  a 
  part 
  of 
  another 
  individual 
  in 
  the 
  same 
  coal 
  slate 
  matrix. 
  

   The 
  cranium 
  and 
  anterior 
  portion 
  of 
  the 
  vertebral 
  column 
  only 
  are 
  preserved, 
  the 
  latter 
  so 
  much 
  injured 
  as 
  to 
  render 
  

   the 
  vertebral 
  characters 
  very 
  obscure. 
  As 
  in 
  the 
  other, 
  the 
  bristle-like 
  scales 
  extend 
  along 
  the 
  dorsal 
  region 
  to 
  

   near 
  the 
  cranium. 
  The 
  anterior 
  § 
  of 
  the 
  ventral 
  side 
  shows 
  a 
  large 
  number 
  of 
  oval 
  scale-like 
  bodies, 
  which 
  

   belonged 
  undoubtedly 
  to 
  the 
  animal, 
  and 
  were 
  probably 
  dermal 
  scales. 
  They 
  are, 
  however, 
  neither 
  regular 
  in 
  

   from 
  nor 
  position. 
  Close 
  behind 
  the 
  head 
  two 
  or 
  three 
  long 
  bones 
  of 
  the 
  fore 
  limbs 
  have 
  been 
  exposed. 
  They 
  are 
  

   slender 
  and 
  similar 
  to 
  those 
  of 
  the 
  last 
  specimen. 
  

  

  The 
  cranium, 
  though 
  without 
  the 
  muzzle, 
  shows 
  its 
  long 
  wedge 
  shape. 
  The 
  maxillary 
  bone 
  cannot 
  be 
  distin- 
  

   guished, 
  nor 
  can 
  the 
  orbits 
  be 
  made 
  out. 
  One 
  ramus 
  mandibuli 
  is 
  pretty 
  well 
  preserved 
  ; 
  it 
  shows 
  no 
  coronoid 
  pro- 
  

   cess. 
  Thirty-one 
  teeth 
  may 
  be 
  counted 
  on 
  a 
  portion 
  a 
  little 
  more 
  than 
  one-third 
  its 
  length. 
  The 
  anterior 
  eleven 
  of 
  

   these 
  are 
  abruptly 
  longer 
  and 
  stouter 
  than 
  the 
  others. 
  They 
  are 
  all, 
  except 
  a 
  few 
  most 
  anterior, 
  in 
  pairs, 
  i. 
  e., 
  with 
  

   a 
  slight 
  vacancy 
  between 
  every 
  two. 
  The 
  larger 
  ones 
  where 
  broken 
  at 
  the 
  bases 
  exhibit 
  a 
  moderate 
  pulp 
  cavity 
  ; 
  

   the 
  smaller, 
  a 
  large 
  one 
  extending 
  to 
  near 
  the 
  lip. 
  Several, 
  though 
  not 
  all 
  of 
  the 
  larger 
  teeth, 
  display 
  a 
  shallow 
  

   groove 
  on 
  the 
  external 
  face 
  to 
  near 
  the 
  tip, 
  which 
  is 
  probably 
  owing 
  to 
  pressure 
  and 
  a 
  partial 
  crushing. 
  The 
  

   points 
  of 
  the 
  larger 
  teeth 
  are 
  more 
  abruptly 
  acute, 
  and 
  turned 
  abruptly 
  _backwards. 
  A 
  portion 
  of 
  their 
  increased 
  

   length 
  (.35) 
  is 
  to 
  be 
  attributed 
  to 
  the 
  splitting 
  oft' 
  of 
  the 
  external 
  dentary 
  margin, 
  and 
  the 
  exposure 
  of 
  the 
  roots. 
  

   No 
  alveoli 
  are 
  shown, 
  and 
  the 
  dentition 
  is 
  probably 
  by 
  anchylosis 
  of 
  expanded 
  base 
  as 
  in 
  true 
  Labyrintliodonts. 
  

  

  A 
  third 
  series, 
  Nos. 
  2G, 
  29, 
  Mus. 
  Newberry, 
  of 
  dorsal 
  vertebra; 
  is 
  without 
  head 
  or 
  limbs. 
  The 
  vertebra 
  are 
  

   elongate, 
  three 
  of 
  them 
  extending 
  over 
  2.10 
  mm. 
  The 
  neural 
  spines 
  are 
  longer 
  than 
  high, 
  and 
  are 
  nearly 
  in 
  

   contact 
  at 
  their 
  margins 
  ; 
  each 
  is 
  marked 
  by 
  about 
  five 
  obtuse 
  vertical 
  ribs. 
  A 
  fractured 
  section 
  of 
  the 
  abdom- 
  

   inal 
  dermal 
  spines 
  in 
  place, 
  displays 
  at 
  least 
  six 
  superimposed 
  layers 
  of 
  them. 
  

  

  