﻿68 
  ON 
  THE 
  NAIADES, 
  

  

  Hab. 
  River 
  Parana, 
  Province 
  of 
  Corrientes. 
  Dr 
  Burrough. 
  

  

  My 
  Cabinet. 
  

  

  Cabinet 
  of 
  Dr 
  Burrough. 
  

  

  Cabinet 
  of 
  the 
  Academy 
  of 
  Natural 
  Sciences 
  of 
  Philadelphia. 
  

  

  Diam. 
  -1, 
  Length 
  1-8, 
  Breadth 
  2*4 
  inches. 
  

  

  Shell 
  subrotund, 
  inequilateral, 
  compressed, 
  subangular 
  behind, 
  with 
  

  

  large 
  oblique 
  folds 
  on 
  the 
  beaks 
  ; 
  substance 
  of 
  the 
  shell 
  rather 
  thick 
  ; 
  

  

  beaks 
  somewhat 
  elevated 
  and 
  distinctly 
  plicate 
  as 
  far 
  as 
  the 
  umbones 
  : 
  

  

  ligament 
  short 
  and 
  thin 
  ; 
  epidermis 
  smooth, 
  dark 
  brown 
  with 
  transverse 
  

  

  yellow 
  marks 
  of 
  growth 
  ; 
  cardinal 
  teeth 
  large, 
  elevated, 
  lamelliform 
  

  

  and 
  double 
  in 
  both 
  valves 
  : 
  lateral 
  teeth 
  lamelliform 
  and 
  nearly 
  straight 
  ; 
  

  

  anterior 
  cicatrices 
  and 
  posterior 
  cicatrices 
  confluent 
  ; 
  dorsal 
  cicatrices 
  

  

  in 
  the 
  centre 
  of 
  the 
  cavity 
  of 
  the 
  beaks 
  ; 
  cavity 
  of 
  the 
  beaks 
  subangular 
  

  

  and 
  shallow; 
  nacre 
  pearly 
  white 
  and 
  iridescent. 
  

  

  Remarks. 
  — 
  This 
  is 
  of 
  the 
  collection 
  of 
  Dr 
  Burrough, 
  sent 
  by 
  him 
  

   to 
  the 
  Academy 
  of 
  Natural 
  Sciences 
  of 
  Philadelphia. 
  To 
  this 
  gentle- 
  

   man 
  natural 
  science 
  is 
  much 
  indebted 
  for 
  his 
  unwearied 
  industry 
  in 
  

   contributing 
  to 
  the 
  knowledge 
  of 
  the 
  Fauna 
  — 
  of 
  the 
  numerous 
  countries 
  

   through 
  which 
  he 
  has 
  travelled, 
  in 
  Asia, 
  as 
  well 
  as 
  on 
  this 
  continent. 
  

   This 
  species 
  resembles 
  most, 
  perhaps, 
  the 
  ladeolus 
  (nobis), 
  but 
  diners 
  

   from 
  it 
  in 
  being 
  more 
  round 
  in 
  the 
  outline, 
  in 
  having 
  longer 
  and 
  larger 
  

   folds 
  on 
  the 
  beaks, 
  and 
  in 
  being 
  more 
  compressed. 
  In 
  the 
  beaks 
  it 
  

   has 
  some 
  resemblance 
  to 
  the 
  corrugatus 
  (Lam.), 
  as 
  well 
  also 
  as 
  in 
  the 
  

   outline 
  ; 
  but 
  the 
  folds 
  being 
  nearly 
  parallel 
  to 
  each 
  other, 
  it 
  differs 
  from 
  

   the 
  corrugatus 
  in 
  these, 
  which 
  are 
  usually 
  zig 
  zag 
  in 
  the 
  latter 
  shell. 
  

   I 
  owe 
  to 
  the 
  kindness 
  of 
  Dr 
  Burrough 
  the 
  specimen 
  in 
  my 
  cabinet, 
  

   and 
  I 
  have 
  great 
  pleasure 
  in 
  dedicating 
  the 
  species 
  to 
  him. 
  

  

  Unio 
  Sowerbianus. 
  Plate 
  X. 
  fig. 
  28. 
  

  

  Testa 
  sublriangulari, 
  inflatd, 
  parte 
  posticd 
  peculiariter 
  compressd 
  et 
  striatd 
  ; 
  

   valvulis 
  crassissimis 
  ; 
  natibus 
  valde 
  prominentibus, 
  dentibus 
  cardinalibus 
  magnis 
  ; 
  

   laleralibus 
  crassis 
  subrectisque 
  ; 
  margaritd 
  in 
  cavo 
  albido-purpured. 
  

  

  