﻿244 
  

  

  G. 
  R. 
  Wieland 
  — 
  Huge 
  Cretaceous 
  Turtles. 
  

  

  Y-shaped 
  bridge, 
  with 
  any 
  vomeral 
  connection 
  very 
  deeply 
  

   set 
  in 
  the 
  skull. 
  (Compare 
  figs. 
  3, 
  4, 
  and 
  5.) 
  

  

  The 
  Mandible* 
  — 
  This 
  was 
  present 
  in 
  position 
  and 
  was 
  quite 
  

   perfect 
  with 
  the 
  exception 
  of 
  the 
  posterior 
  elements 
  of 
  the 
  left 
  

   ramus, 
  which 
  were 
  dissociated, 
  only 
  the 
  surangular 
  being 
  

   recovered. 
  The 
  measurements 
  appended 
  may 
  be 
  taken 
  as 
  quite 
  

  

  Figure 
  4. 
  Thalassochelys 
  caretta, 
  palatal 
  view 
  of 
  skull 
  x 
  1/5. 
  

  

  Figure 
  5. 
  Dermochelys 
  coriacea 
  " 
  " 
  " 
  x 
  1/5. 
  

  

  pm, 
  premaxillary 
  ; 
  m, 
  maxillary 
  ; 
  pi, 
  palatal; 
  v, 
  vomer; 
  pt, 
  ptery- 
  

   goid; 
  bs, 
  basi 
  sphenoid; 
  q, 
  quadrate; 
  s, 
  squamosal. 
  

  

  accurate, 
  the 
  complementary 
  and 
  articular 
  being 
  the 
  only 
  parts 
  

   much 
  altered 
  by 
  pressure. 
  As 
  the 
  latter 
  is 
  very 
  much 
  flattened 
  

   and 
  the 
  parts 
  bounding 
  it 
  but 
  little 
  compressed, 
  it 
  may 
  not 
  

   have 
  been 
  well 
  ossified. 
  

  

  From 
  the 
  apparent 
  shortness 
  of 
  the 
  rami, 
  no 
  less 
  however 
  

   than 
  in 
  the 
  land 
  turtle 
  Macrochelys 
  Temminckii, 
  it 
  may 
  be 
  

   fairly 
  inferred 
  that 
  both 
  the 
  articular 
  and 
  the 
  articular 
  face 
  of 
  

   the 
  quadrate 
  were 
  heavily 
  encased 
  in 
  cartilage. 
  This 
  is 
  also 
  

   suggested 
  by 
  the 
  roughened 
  to 
  spongiose 
  appearance 
  of 
  both 
  

   these 
  parts. 
  The 
  horn 
  sheath 
  of 
  the 
  beak 
  must 
  also 
  have 
  been 
  

   very 
  heavy 
  and 
  somewhat 
  upturned. 
  

  

  The 
  general 
  relationship 
  of 
  the 
  present 
  form 
  to 
  Protostega 
  

   is 
  strongly 
  exemplified 
  by 
  the 
  lower 
  jaw. 
  The 
  presplenial 
  of 
  

   Baur 
  (2) 
  is 
  however 
  apparently 
  less 
  prominent 
  than 
  in 
  that 
  

   fossil 
  (see 
  Case, 
  5), 
  the 
  suture 
  between 
  it 
  and 
  the 
  splenial 
  not 
  

  

  *I 
  retain 
  the 
  original 
  nomenclature 
  for 
  the 
  mandibular 
  parts, 
  not 
  being 
  as 
  yet 
  

   able 
  to 
  reconcile 
  that 
  proposed 
  by 
  Dr. 
  Baur 
  (2) 
  with 
  the 
  conditions 
  found 
  in 
  the 
  

   Testudinata, 
  and 
  hoping 
  later 
  to 
  present 
  a 
  paper 
  on 
  the 
  homologies 
  of 
  the 
  reptil- 
  

   ian 
  lower 
  jaw. 
  

  

  