﻿122-B 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  lar 
  form, 
  but 
  the 
  extremities 
  are 
  plane. 
  The 
  posterior 
  basis 
  of 
  the 
  neural 
  arch 
  is 
  on 
  the 
  

   posterior 
  third 
  of 
  the 
  upper 
  surface, 
  and 
  the 
  anterior 
  end 
  has 
  evidently 
  supported 
  its 
  an- 
  

   terior 
  part. 
  They 
  leave 
  the 
  median 
  third 
  of 
  the 
  canal 
  open 
  laterally, 
  its 
  median 
  surface 
  

   passing 
  into 
  the 
  external 
  over 
  a 
  lateral 
  shoulder. 
  The 
  arch 
  probably 
  bridged 
  over 
  this 
  

   interval. 
  The 
  chevron 
  bone 
  is 
  long 
  and 
  wide, 
  and 
  with 
  thin 
  walls. 
  A 
  second 
  caudal 
  ex- 
  

   hibits 
  similar 
  characters. 
  Two 
  adjacent 
  caudals 
  in 
  the 
  same 
  piece 
  of 
  matrix 
  exhibit 
  

   shorter, 
  deeper 
  centra, 
  with 
  strongly 
  concave 
  inferior 
  surfaces, 
  which 
  are 
  separated 
  from 
  

   the 
  laterals 
  by 
  an 
  obtuse 
  longitudinal 
  angle. 
  Articular 
  faces 
  concave, 
  forming 
  vertical 
  

   ovals 
  truncate 
  below. 
  The 
  chevron 
  bones 
  are 
  narrower, 
  directed 
  backwards, 
  and 
  of 
  very 
  

   light 
  construction. 
  The 
  neurapophyses 
  present 
  the 
  singular 
  character 
  indicated 
  above. 
  

   Their 
  contact 
  with 
  the 
  centrum 
  is 
  anterior 
  and 
  posterior 
  only, 
  their 
  basis 
  being 
  excavated 
  

   upwards 
  into 
  a 
  regular 
  arch, 
  whose 
  margins 
  flare 
  out 
  a 
  little. 
  This 
  remarkable 
  structure 
  

   is 
  only 
  paralleled 
  in 
  the 
  sacrum 
  of 
  other 
  Dinosauria, 
  where 
  the 
  nerves 
  destined 
  for 
  the 
  

   sacral 
  plexus, 
  issue 
  through 
  huge 
  foramina 
  in 
  the 
  bases 
  of 
  the 
  neurapophyses. 
  Here 
  the 
  

   structure 
  is 
  continued 
  on 
  the 
  caudals, 
  and 
  evidently 
  for 
  a 
  very 
  different 
  purpose. 
  The 
  

   neural 
  arch 
  has 
  a 
  high 
  longitudinal 
  carina, 
  which 
  is 
  continued 
  in 
  the 
  neural 
  spine. 
  It 
  is 
  

   concave 
  on 
  each 
  side 
  between 
  the 
  zygapophyses. 
  The 
  posterior 
  zygapophyses 
  stand 
  above 
  

   an 
  intervertebral 
  space, 
  and 
  the 
  narrow 
  neural 
  spine 
  rises 
  above 
  them, 
  as 
  is 
  usual 
  in 
  Dino- 
  

   sauria. 
  The 
  zygapophysial 
  faces 
  make 
  about 
  an 
  angle 
  of 
  45°. 
  A 
  distal 
  caudal 
  is 
  slender, 
  

   sub-cylindric, 
  and 
  with 
  low 
  neural 
  arch. 
  

  

  The 
  right 
  anterior 
  foot 
  displays 
  five 
  digits, 
  though 
  one 
  of 
  them 
  opposite 
  the 
  ex- 
  

   tremity 
  of 
  the 
  ulna, 
  was 
  very 
  short. 
  The 
  phalanges 
  are, 
  from 
  without, 
  1 
  — 
  3 
  — 
  4 
  — 
  3 
  — 
  2; 
  

   they 
  are" 
  short 
  and 
  stout, 
  the 
  ungues 
  short, 
  deep, 
  much 
  curved 
  and 
  compressed. 
  That 
  of 
  

   the 
  interior 
  digit 
  is 
  the 
  largest 
  ; 
  the 
  inner 
  edge 
  is 
  rounded, 
  the 
  superior 
  broad 
  and 
  slightly 
  

   flattened. 
  At 
  the 
  middle 
  of 
  its 
  length, 
  a 
  shallow 
  groove 
  near 
  the 
  dorsal 
  outline 
  begins 
  to 
  

   contract 
  to 
  a 
  sharply 
  defined, 
  narrow 
  groove, 
  which 
  continues 
  to 
  the 
  end 
  of 
  the 
  claw. 
  The 
  

   trochlear 
  faces 
  are 
  well 
  distinguished. 
  The 
  phalanges 
  are 
  stout 
  and 
  with 
  a 
  marked 
  liga- 
  

   mentous 
  pit 
  on 
  each 
  side 
  distally. 
  The 
  metacarpals 
  of 
  the 
  two 
  middle 
  digits 
  are 
  slender 
  

   and 
  twice 
  as 
  long 
  as 
  the 
  adjacent 
  phalanges; 
  that 
  of 
  the 
  outer 
  digit 
  is 
  one-third 
  shorter, 
  and 
  

   that 
  of 
  the 
  inner, 
  one-half 
  shorter 
  than 
  the 
  median. 
  The 
  fourth 
  metatarsus 
  is 
  longer 
  than 
  

   the 
  external, 
  but 
  much 
  more 
  slender 
  than 
  any 
  other. 
  This 
  finger 
  was 
  shorter 
  than 
  the 
  

   third, 
  and 
  probably 
  possessed 
  three 
  phalanges 
  ; 
  portions 
  of 
  two 
  are 
  preserved, 
  and 
  the 
  

   most 
  distal 
  is 
  not 
  ungual. 
  

  

  The 
  extremity 
  of 
  the 
  ulna 
  larger 
  than 
  that 
  of 
  the 
  radius 
  and 
  rather 
  more 
  expanded. 
  

   Both 
  bones 
  of 
  the 
  fore 
  arm 
  are 
  very 
  pneumatic, 
  and 
  oval 
  in 
  section. 
  

  

  The 
  femur 
  is 
  represented 
  by 
  both 
  extremities 
  with 
  shaft 
  adjacent, 
  and 
  that 
  part 
  of 
  the 
  

   shaft 
  supporting 
  the 
  third 
  trochanter. 
  It 
  is 
  peculiar 
  in 
  presenting 
  a 
  combination 
  of 
  char- 
  

  

  