﻿AND 
  AYES 
  OF 
  NORTH 
  AMERICA. 
  21 
  

  

  series 
  of 
  caudal 
  vertebra? 
  is 
  quite 
  short, 
  and 
  the 
  ribs 
  are 
  short 
  and 
  but 
  little 
  curved, 
  hi 
  

   Molgophis 
  the 
  tail 
  lias 
  been 
  like 
  that 
  of 
  an 
  elongate 
  serpent, 
  and 
  the 
  ribs 
  are 
  as 
  well 
  

   developed 
  as 
  those 
  of 
  many 
  reptiles. 
  

  

  Though 
  no 
  limbs 
  or 
  arches 
  can 
  be 
  certainly 
  found, 
  a 
  rather 
  quadrate, 
  parallelogrammie 
  

   piece, 
  about 
  as 
  long 
  as 
  the 
  diameter 
  of 
  a 
  vertebra, 
  may 
  be 
  found. 
  This 
  is 
  however 
  very 
  

   doubtful. 
  

  

  The 
  characters 
  of 
  the 
  genus 
  are 
  : 
  a 
  long 
  serpentine 
  body, 
  without 
  dermal 
  armature, 
  so 
  

   far 
  as 
  discoverable 
  ; 
  the 
  vertebrae 
  large 
  and 
  broad 
  with 
  very 
  prominent 
  zygapophyses 
  and 
  

   moderate 
  neural 
  spine, 
  those 
  of 
  the 
  caudals 
  without 
  narrowed 
  bases 
  (and 
  grooved 
  or 
  

   serrate 
  edges, 
  most 
  probably). 
  Limbs 
  and 
  cranium 
  unknown. 
  

  

  This 
  genus 
  differs 
  from 
  Urocordylus 
  in 
  its 
  caudal 
  vertebra?, 
  and 
  from 
  Ophiderpeton 
  in 
  

   its 
  dorsals: 
  the 
  latter 
  in 
  their 
  zygapophyses 
  projecting 
  laterally 
  resemble 
  those 
  of 
  Amphi- 
  

   uma. 
  It 
  differs 
  from 
  CEstocephalus 
  in 
  the 
  absence 
  of 
  ventral 
  dermal 
  bands 
  and 
  in 
  the 
  

   longer 
  body, 
  without 
  indication 
  of 
  limbs. 
  The 
  size 
  of 
  the 
  vertebra 
  1 
  would 
  indicate 
  a 
  body 
  

   of 
  the 
  size 
  of 
  a 
  rattlesnake, 
  ((7. 
  horrida,) 
  and 
  therefore 
  too 
  large 
  for 
  the 
  species 
  named 
  

   Brachydectes 
  newberryi. 
  

  

  The 
  ribs 
  are 
  long, 
  and 
  though 
  the 
  head 
  is 
  not 
  bifurcate, 
  there 
  appear 
  to 
  be 
  both 
  

   tubercle 
  and 
  head 
  on 
  the 
  dilated 
  extremity. 
  They 
  show 
  themselves 
  where 
  crushed 
  to 
  

   have 
  a 
  large 
  median 
  vacuity. 
  

  

  MOLGOPHIS 
  MACRITRTJS, 
  Cope. 
  

  

  The 
  neural 
  arches 
  viewed 
  from 
  ahove 
  have 
  a 
  posterior 
  Y-shaped 
  outline, 
  from 
  the 
  fact 
  that 
  the 
  broad 
  zygapo- 
  

   physes 
  meet 
  on 
  the 
  median 
  line, 
  and 
  spread 
  out 
  distally 
  over 
  the 
  broad 
  anterior 
  ones 
  adjoining. 
  The 
  latter 
  appear 
  to 
  

   be 
  somewhat 
  concave, 
  and 
  to 
  border 
  the 
  former 
  exteriorly 
  as 
  well 
  as 
  inferiorly. 
  The 
  base 
  of 
  the 
  neural 
  spine 
  extends 
  

   to 
  the 
  posterior 
  emargination, 
  but 
  not 
  quite 
  to 
  the 
  anterior. 
  The 
  breadth 
  of 
  the 
  dorsal 
  vertebra 
  above 
  is 
  equal 
  from 
  

   the 
  emargination 
  behind 
  to 
  the 
  anterior 
  margin 
  of 
  the 
  anterior 
  zygapophysis. 
  

  

  The 
  caudal 
  series 
  must 
  have 
  been 
  very 
  long, 
  as 
  there 
  is 
  very 
  little 
  diminution 
  in 
  the 
  size 
  of 
  the 
  vertebrae 
  through- 
  

   out 
  the 
  series 
  preserved. 
  They 
  present 
  much 
  the 
  same 
  form 
  as 
  the 
  dorsals, 
  but 
  are 
  more 
  contracted 
  medially, 
  and 
  

   the 
  zygapophyses 
  have 
  a 
  more 
  transverse 
  direction. 
  There 
  may 
  indeed 
  be 
  a 
  cliapophysial 
  element 
  beneath 
  these, 
  but 
  

   the 
  two 
  cannot 
  be 
  distinguished 
  if 
  so. 
  They 
  are 
  connected 
  by 
  longitudial 
  impressions, 
  indicating 
  the 
  existence 
  of 
  

   the 
  tendinous 
  bands 
  in 
  the 
  longitudinal 
  muscles 
  seen 
  in 
  Amphiunna, 
  or 
  the 
  osseous 
  spicules 
  in 
  the 
  same 
  situation 
  in 
  

   birds. 
  The 
  neural 
  spines 
  indicated 
  by 
  their 
  narrow 
  bases, 
  occupied 
  the 
  length 
  of 
  the 
  neural 
  arch, 
  and 
  remind 
  one 
  of 
  

   Amphiuma. 
  

  

  The 
  ribs 
  are 
  long 
  for 
  a 
  Batrachian, 
  but 
  shorter 
  than 
  in 
  a 
  reptile. 
  They 
  are 
  well 
  curved, 
  chiefly 
  near 
  the 
  proximal 
  

   extremity. 
  The 
  longest 
  I 
  can 
  find 
  measured 
  by 
  a 
  chord, 
  equals 
  two 
  vertebrae 
  and 
  two-fifths. 
  Three 
  vertebra; 
  

   measured 
  along 
  the 
  median 
  line 
  above 
  equal 
  eleven 
  lines 
  ; 
  one 
  of 
  these 
  is 
  3.6 
  lines 
  in 
  width 
  above 
  ; 
  width 
  of 
  a 
  (?) 
  

   posterior 
  caudal 
  3 
  1. 
  

  

  This 
  animal 
  has 
  been 
  like 
  Amphiuma 
  a 
  snake-like 
  Batrachian, 
  but 
  probably 
  of 
  even 
  more 
  elongate 
  form. 
  How 
  

   near 
  its 
  affinities 
  to 
  this 
  genus 
  may 
  be, 
  cannot 
  be 
  ascertained, 
  owing 
  to 
  want 
  of 
  important 
  parts 
  of 
  the 
  skeleton, 
  but 
  

   it 
  differs 
  in 
  the 
  important 
  featm 
  - 
  e 
  of 
  the 
  large, 
  well 
  developed 
  ribs. 
  

  

  AMERT. 
  PHILOSO. 
  SOC— 
  VOL. 
  XIV. 
  6 
  

  

  