﻿SPINY 
  SOFT-SHELLED 
  TURTLE. 
  419 
  

  

  Family 
  TRIONYCHIDAE. 
  

  

  Amyda 
  spinifera 
  (Le 
  Sueur). 
  

  

  Spiny 
  Soft-shelled 
  Turtle. 
  

  

  Plate 
  32. 
  

  

  Trionyx 
  spiniferus 
  Le 
  Sueur, 
  Mem. 
  Mus. 
  d'Hist. 
  Nat. 
  Paris, 
  Dec. 
  1827, 
  vol. 
  15, 
  p. 
  258, 
  pi. 
  6. 
  

   Amyda 
  spinifera 
  Hurler, 
  Trans. 
  Acad. 
  Sji. 
  St. 
  Louis, 
  1911, 
  vol. 
  20, 
  p. 
  251. 
  

  

  The 
  Spiny 
  Soft-shelled 
  Turtle 
  belongs 
  to 
  a 
  family 
  of 
  Chelonians 
  which 
  next 
  to 
  the 
  sea 
  

   tvirtles, 
  is 
  the 
  most 
  persistently 
  aquatic 
  in 
  its 
  habits. 
  

  

  Size. 
  — 
  The 
  measurements 
  of 
  a 
  mature 
  female 
  specimen 
  are: 
  length 
  of 
  carapace, 
  14 
  inches; 
  

   width 
  of 
  carapace, 
  12; 
  length 
  of 
  plastron, 
  10; 
  length 
  of 
  tail, 
  3 
  J; 
  width 
  of 
  head, 
  If; 
  width 
  of 
  

   spread 
  hind 
  foot, 
  3|; 
  weight, 
  7| 
  pounds 
  (Ditmars, 
  1907, 
  p. 
  77). 
  

  

  Thompson 
  (1853, 
  p. 
  30) 
  gives 
  the 
  measurements 
  of 
  three 
  Vermont 
  (Lake 
  Champlain) 
  

   specimens 
  as 
  follows: 
  

  

  Length 
  Breadth 
  Height 
  

  

  No. 
  1 
  11 
  inches 
  9.5 
  inches 
  2.2 
  inches 
  

  

  No. 
  2 
  13 
  " 
  10.75 
  " 
  3.2 
  " 
  

  

  No. 
  3 
  13.5 
  " 
  11 
  " 
  3.5 
  " 
  

  

  Color. 
  — 
  The 
  carapace 
  is 
  dull 
  olive 
  or 
  yellowish 
  brown. 
  The 
  plastron 
  is 
  white, 
  having 
  a 
  

   narrow 
  yellow 
  border, 
  internally 
  margined 
  with 
  black. 
  In 
  young 
  specimens 
  the 
  carapace 
  is 
  

   dotted 
  all 
  over 
  with 
  small 
  ocellated 
  spots 
  which 
  increase 
  in 
  size 
  with 
  age 
  and 
  finally 
  fade 
  into 
  

   irregular 
  blotches. 
  The 
  head 
  is 
  oUve-colored 
  and 
  on 
  each 
  side 
  is 
  a 
  yellow 
  black-bordered 
  stripe 
  

   which 
  extends 
  from 
  the 
  neck 
  through 
  the 
  eye 
  and 
  meets 
  its 
  fellow 
  at 
  the 
  base 
  of 
  the 
  snout. 
  

   The 
  extremities 
  are 
  brownish 
  or 
  olive, 
  blotched 
  with 
  black. 
  

  

  Description. 
  — 
  The 
  body 
  is 
  strikingly 
  flat 
  and 
  bluntly 
  oval, 
  covered 
  with 
  soft 
  leathery 
  

   skin 
  instead 
  of 
  with 
  horny 
  shields. 
  The 
  ossification 
  of 
  the 
  carapace 
  is 
  very 
  incomplete 
  peri- 
  

   pherally, 
  the 
  ribs 
  extending 
  considerably 
  beyond 
  the 
  costal 
  plates. 
  The 
  marginal 
  plates 
  are 
  

   absent, 
  so 
  that 
  the 
  edge 
  of 
  the 
  carapace 
  droops 
  like 
  a 
  flap 
  over 
  the 
  head 
  and 
  extremities. 
  The 
  

   carapace 
  sometimes 
  presents 
  a 
  keel 
  and 
  well 
  defined 
  rugosities, 
  and 
  in 
  adult 
  and 
  old 
  specimens 
  

   there 
  are 
  prominent 
  conical 
  spiny 
  tubercles 
  on 
  the 
  anterior 
  margin. 
  The 
  plastron 
  also 
  is 
  

   imperfectly 
  ossified, 
  the 
  bones 
  being 
  much 
  reduced 
  and 
  only 
  loosely 
  associated. 
  The 
  head 
  

   and 
  neck 
  are 
  wholly 
  retractile, 
  bending 
  by 
  a 
  sigmoid 
  curve 
  in 
  a 
  vertical 
  plane. 
  The 
  jaws 
  

   which 
  are 
  sharp 
  and 
  powerful 
  are 
  concealed 
  by 
  soft, 
  lip-like 
  flaps, 
  and 
  the 
  nose 
  forms 
  a 
  soft, 
  

   slender 
  tube-shaped 
  proboscis. 
  This 
  prolongation 
  of 
  the 
  nostrils 
  into 
  a 
  leathery 
  tube 
  is 
  an 
  

  

  