﻿298 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol.96 
  

  

  The 
  lower 
  jaw, 
  as 
  in 
  Testudo 
  generally, 
  is 
  massive 
  and 
  heavy. 
  Its 
  

   length 
  from 
  the 
  symphysis 
  to 
  the 
  angle 
  is 
  59 
  mm., 
  height 
  at 
  the 
  

   coronoid 
  process 
  59 
  mm., 
  height 
  at 
  the 
  symphysis 
  10.5 
  mm. 
  The 
  

   masticatory 
  surface 
  is 
  traversed 
  longitudinally 
  by 
  a 
  deep 
  groove. 
  

   Inner 
  cutting 
  edge 
  of 
  the 
  mandible 
  is 
  nearly 
  as 
  high 
  as 
  the 
  outer. 
  

   Inner 
  cutting 
  edge 
  of 
  the 
  rami 
  is 
  separated 
  by 
  a 
  notch 
  at 
  the 
  sym- 
  

   physis; 
  cutting 
  edge 
  not 
  denticulated. 
  The 
  extent 
  of 
  the 
  several 
  

   elements 
  forming 
  the 
  mandible 
  is 
  clearly 
  shown 
  in 
  figures 
  21 
  and 
  23. 
  

  

  Figure 
  24. 
  — 
  Carapace 
  of 
  Testudo 
  praeextans 
  Lambe, 
  type 
  (C. 
  N. 
  M. 
  No. 
  8401): 
  1, 
  2, 
  3, 
  4, 
  

   5, 
  6, 
  7, 
  8, 
  neurals 
  1-8, 
  respectively. 
  One-sixth 
  natural 
  size. 
  

  

  Carapace. 
  — 
  In 
  the 
  general 
  contour 
  of 
  the 
  carapace 
  and 
  plastron, 
  

   but 
  more 
  especially 
  in 
  the 
  depressed 
  character 
  of 
  the 
  shell 
  as 
  a 
  whole, 
  

   all 
  these 
  specimens 
  are 
  in 
  close 
  agreement 
  with 
  the 
  type 
  of 
  the 
  species. 
  

   The 
  carapaces 
  of 
  all 
  are 
  flattened 
  on 
  top 
  in 
  the 
  vertebral 
  region 
  and 
  

   when 
  viewed 
  from 
  the 
  side 
  present 
  a 
  nearly 
  straight 
  profile 
  except 
  

   where 
  they 
  curve 
  downward 
  at 
  the 
  ends. 
  This 
  depression 
  of 
  the 
  cara- 
  

   pace, 
  with 
  the 
  exception 
  of 
  Testudo 
  laticunea 
  Cope, 
  appears 
  to 
  dis- 
  

   tinguish 
  this 
  species 
  from 
  all 
  other 
  North 
  American 
  members 
  of 
  the 
  

   genus. 
  Among 
  the 
  large 
  land 
  tortoises 
  only 
  Testudo 
  grandidieri 
  

   VaUlant, 
  of 
  northern 
  Madagascar, 
  has 
  a 
  somewhat 
  simUar 
  depressed 
  

   and 
  flattened 
  shell. 
  

  

  The 
  four 
  specimens 
  under 
  discussion 
  show 
  a 
  considerable 
  difference 
  

   in 
  size 
  of 
  the 
  shell, 
  as 
  indicated 
  in 
  table 
  1. 
  

  

  