﻿28 
  ON 
  THE 
  NAIADES 
  

  

  Unio 
  Nicklinianus. 
  Plate 
  I. 
  figr. 
  1. 
  

  

  &' 
  

  

  Testa 
  subtrigond, 
  insequilaterali, 
  obliqud, 
  maxime 
  undulatd, 
  usque 
  ad 
  natium 
  

   apices; 
  valvulis 
  crassissimis 
  ; 
  dentibus 
  lateralibus 
  crassis 
  curvisque 
  ; 
  cardinalibus 
  

   maxime 
  O'assis; 
  margaritd 
  alba 
  et 
  iridescente. 
  

  

  Shell 
  subtriangular, 
  inequilateral, 
  oblique, 
  very 
  much 
  undulated, 
  even 
  to 
  the 
  point 
  

   of 
  the 
  beak; 
  valves 
  very 
  thick; 
  cardinal 
  teeth 
  very 
  thick; 
  lateral 
  teeth 
  thick 
  and 
  

   curved 
  ; 
  nacre 
  pearly 
  white 
  and 
  iridescent. 
  

  

  Hab. 
  China. 
  

  

  My 
  Cabinet. 
  

   Diam. 
  2, 
  Length 
  5, 
  Breadth 
  5-8 
  inches. 
  

  

  Shell 
  subtriangular, 
  oblique, 
  very 
  much 
  spread 
  out, 
  with 
  an 
  elevated 
  

   wing, 
  flattened 
  towards 
  the 
  beaks, 
  the 
  greatest 
  diameter 
  being 
  near 
  the 
  

   posterior 
  basal 
  margin, 
  covered 
  with 
  numerous 
  undulations, 
  except 
  on 
  

   the 
  anterior 
  and 
  basal 
  margins 
  ; 
  undulations 
  diverge 
  from 
  the 
  beak, 
  and 
  

   are 
  largest 
  near 
  the 
  posterior 
  margin 
  : 
  substance 
  of 
  the 
  shell 
  very 
  thick 
  

   in 
  the 
  region 
  of 
  the 
  basal 
  margin 
  ; 
  beaks 
  pointed 
  but 
  not 
  elevated, 
  cov- 
  

   ered 
  with 
  numerous 
  beautiful 
  Iterations 
  to 
  the 
  very 
  point 
  ; 
  epidermis 
  

   dark 
  brown 
  ; 
  cardinal 
  teeth 
  very 
  large, 
  thick 
  and 
  sulcate 
  ; 
  lateral 
  teeth 
  

   thick 
  and 
  curved 
  ; 
  anterior 
  cicatrices 
  rough 
  and 
  distinct 
  ; 
  posterior 
  cica- 
  

   trices 
  slight 
  and 
  confluent 
  ; 
  dorsal 
  cicatrices 
  situated 
  on 
  the 
  under 
  side 
  

   of 
  the 
  cardinal 
  tooth 
  ; 
  cavity 
  of 
  the 
  beaks 
  angular 
  ; 
  nacre 
  pearly 
  white, 
  

   very 
  iridescent 
  on 
  the 
  posterior 
  part, 
  where 
  the 
  undulations 
  are 
  visible 
  

   from 
  without. 
  

  

  Remarks. 
  — 
  I 
  met 
  with 
  this 
  very 
  interesting 
  species 
  in 
  the 
  autumn 
  of 
  

   1S31 
  at 
  a 
  dealer's 
  in 
  New 
  York. 
  I 
  was 
  informed 
  that 
  it 
  was 
  supposed 
  

   to 
  be 
  from 
  China. 
  A 
  single 
  valve 
  only 
  could 
  be 
  obtained, 
  and 
  this 
  

   unfortunately 
  not 
  entirely 
  perfect. 
  The 
  characters 
  are, 
  however, 
  so 
  

   distinct 
  from 
  any 
  species 
  I 
  have 
  seen, 
  that 
  I 
  have 
  not 
  hesitated 
  to 
  give 
  

   it 
  a 
  place 
  among 
  my 
  new 
  species. 
  It 
  is 
  remarkable 
  for 
  its 
  great 
  extent 
  

   from 
  the 
  top 
  of 
  the 
  wing 
  to 
  the 
  basal 
  margin, 
  and 
  for 
  its 
  numerous 
  

   undulations. 
  In 
  outline 
  and 
  diameter 
  it 
  resembles 
  the 
  Symphynota 
  

   complanata 
  (nobis) 
  (Alasmodonta 
  complanata 
  of 
  Barnes), 
  but 
  diners 
  in 
  

   being 
  less 
  transverse, 
  higher 
  in 
  the 
  wing, 
  and 
  more 
  thickly 
  covered 
  

  

  