﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  123 
  

  

  TESTUDIIVATA. 
  

  

  CBYPTODIRA. 
  

  

  EMYDIDAE. 
  

  

  EMYDINAE. 
  

  

  STYLEMYS, 
  Leidy. 
  

  

  Stylemys, 
  Testudo 
  and 
  Emys, 
  Leidy, 
  Proceed. 
  Ac. 
  N. 
  Sci., 
  1851, 
  172. 
  Testudo, 
  Leidy 
  1. 
  c. 
  1852, 
  59. 
  Smithson. 
  

   Contrib. 
  to 
  Knowl., 
  1852, 
  103. 
  

  

  The 
  species 
  which 
  I 
  refer 
  to 
  this 
  genus, 
  are 
  Emycloids 
  with 
  the 
  usual 
  elongate 
  form 
  

   of 
  digits 
  which 
  characterizes 
  the 
  aquatic 
  species, 
  but 
  with 
  a 
  single 
  caudal 
  marginal 
  scutum, 
  

   as 
  in 
  Testudo. 
  Another 
  Emydoid 
  genus 
  which 
  approaches 
  Testudo 
  most, 
  is 
  Manuria, 
  

   Gray. 
  Here 
  however 
  the 
  anal 
  marginal 
  plate 
  is 
  divided, 
  and 
  the 
  pectoral 
  plates 
  do 
  not 
  

   meet 
  on 
  the 
  median 
  line. 
  In 
  Stylemys 
  the 
  latter 
  are 
  only 
  narrowed. 
  

  

  The 
  ilium 
  is 
  formed 
  much 
  as 
  in 
  Chelydra, 
  somewhat 
  dilated 
  proximally 
  in 
  a 
  posterior 
  

   direction. 
  The 
  pubis 
  is 
  like 
  some 
  Emydoids 
  in 
  the 
  length 
  and 
  lateral 
  direction 
  of 
  its 
  

   lateral 
  process, 
  while 
  its 
  stout 
  form, 
  with 
  distal 
  dilatation, 
  articulated 
  with 
  its 
  fellow 
  on 
  

   the 
  median 
  line 
  is 
  like 
  that 
  of 
  Chelydra. 
  

  

  A 
  right 
  femur 
  is 
  entirely 
  Testudinoid, 
  and 
  presents 
  one 
  peculiarity 
  which 
  I 
  have 
  only 
  

   observed 
  in 
  Testudo 
  polyphemus. 
  The 
  great 
  trochanter 
  (which 
  is 
  always 
  large 
  in 
  the 
  

   Testudinata) 
  extends 
  entirely 
  round 
  from 
  its 
  origin, 
  to 
  near 
  the 
  head 
  of 
  the 
  femur, 
  em- 
  

   bracing 
  a 
  marked 
  fossa. 
  In 
  other 
  genera 
  the 
  greater 
  tuberosity 
  with 
  the 
  lesser 
  enclose 
  a 
  

   fossa-like 
  groove, 
  which 
  separates 
  them 
  entirely. 
  

  

  The 
  capitula 
  of 
  the 
  ribs 
  extend 
  to 
  the 
  vertebrae, 
  but 
  not 
  to 
  their 
  centra 
  ; 
  they 
  are 
  in 
  

   contact 
  with 
  the 
  laminiform 
  neural 
  spines. 
  

  

  A 
  marked 
  character 
  of 
  the 
  genus 
  also 
  consists 
  in 
  the 
  considerable 
  separation 
  of 
  the 
  

   neural 
  arch 
  from 
  the 
  vertebral 
  carapacial 
  bones. 
  It 
  is 
  suspended 
  as 
  it 
  were, 
  some 
  distance 
  

   below 
  them 
  by 
  the 
  laminiform 
  elevation 
  of 
  the 
  joined 
  neurapophyses, 
  which 
  are 
  united 
  by 
  

   suture 
  to 
  the 
  similar 
  thin 
  plate-like 
  neural 
  spines, 
  which 
  descend 
  from 
  the 
  transverse 
  

   vertebral 
  expansions. 
  The 
  depth 
  of 
  this 
  vertebral 
  septum 
  is 
  greater 
  than 
  the 
  length 
  of 
  

   each 
  vertebral 
  bone, 
  behind 
  the 
  middle 
  of 
  the 
  column. 
  The 
  centra 
  are 
  very 
  thin 
  as 
  in 
  

   Cistudo. 
  

  

  Leidy 
  named 
  some 
  individuals 
  of 
  one 
  of 
  the 
  species, 
  Stylemys, 
  while 
  others 
  were 
  

   referred 
  to 
  Emys. 
  As 
  he 
  gave 
  no 
  characters 
  to 
  it, 
  and 
  afterwards 
  abandoned 
  it, 
  referring 
  

   the 
  species 
  to 
  Testudo, 
  I 
  only 
  adopt 
  the 
  name 
  for 
  the 
  purpose 
  of 
  diminishing 
  the 
  synonymy. 
  

  

  