﻿62 
  ON 
  THE 
  NAIADES, 
  

  

  interrupted 
  one 
  like 
  the 
  pustulosus. 
  There 
  is 
  a 
  great 
  peculiarity 
  in 
  

   the 
  flesh 
  or 
  pink 
  colour 
  of 
  the 
  nacre, 
  which 
  is 
  disposed 
  to 
  be 
  clouded, 
  

   and 
  to 
  be 
  of 
  a 
  stronger 
  hue 
  about 
  the 
  teeth, 
  while 
  the 
  cavity 
  of 
  the 
  

   beak 
  is 
  nearly 
  white. 
  

  

  I 
  dedicate 
  this 
  species 
  to 
  my 
  friend, 
  William 
  Cooper, 
  Esq., 
  as 
  a 
  slight 
  

   acknowledgement 
  of 
  the 
  many 
  favours 
  received 
  in 
  the 
  way 
  of 
  commu- 
  

   nications, 
  and 
  the 
  loan 
  of 
  specimens. 
  

  

  Unio 
  emarginatus. 
  Plate 
  IX. 
  fig. 
  22. 
  

  

  Testa 
  sub-ellipticd, 
  ad 
  basim 
  emarginatd 
  et 
  compressd, 
  transversissimd, 
  valde 
  

   insequilaterd, 
  postice 
  sub-triangulatd 
  ; 
  valvulis 
  subcrassis 
  ; 
  natibus 
  prominulis, 
  

   apicibus 
  undulatis 
  ; 
  epidermide 
  viridi-luted 
  ; 
  dentibus 
  cardinalibus 
  parvis, 
  obliquis, 
  

   et 
  in 
  valvula 
  utrdque 
  duplicibus 
  ; 
  lateralibus 
  longis 
  subcurvisque 
  ; 
  margaritd 
  

   albd 
  et 
  iridescente. 
  

  

  Shell 
  sub-elliptical, 
  emarginate 
  and 
  compressed 
  at 
  base, 
  very 
  transverse, 
  very 
  inequi- 
  

   lateral, 
  sub-biangular 
  behind; 
  valves 
  somewhat 
  thick; 
  beaks 
  rather 
  elevated 
  and 
  undu- 
  

   lated 
  at 
  tip 
  ; 
  epidermis 
  greenish 
  yellow 
  ; 
  cardinal 
  teeth 
  small, 
  oblique 
  and 
  double 
  in 
  

   both 
  valves 
  ; 
  lateral 
  teeth 
  long 
  and 
  slightly 
  curved 
  ; 
  nacre 
  pearly 
  white 
  and 
  iridescent. 
  

  

  Hab 
  

  

  My 
  Cabinet. 
  

   Diam. 
  1, 
  Length 
  1-3, 
  Breadth 
  2-8 
  inches. 
  

  

  Shell 
  subelliptical, 
  emarginate 
  and 
  compressed 
  at 
  base, 
  very 
  trans- 
  

   verse, 
  very 
  inequilateral, 
  sub-biangular 
  behind, 
  elevated 
  along 
  the 
  urn- 
  

   bonial 
  slope, 
  flattened 
  on 
  the 
  umbones 
  ; 
  substance 
  of 
  the 
  shell 
  somewhat 
  

   thick 
  ; 
  beaks 
  rather 
  elevated, 
  retuse 
  and 
  undulate 
  at 
  the 
  tip 
  ; 
  ligament 
  

   long 
  and 
  thin 
  ; 
  epidermis 
  finely 
  wrinkled, 
  greenish 
  yellow, 
  along 
  the 
  

   posterior 
  slope 
  green 
  ; 
  cardinal 
  teeth 
  small, 
  oblique 
  and 
  double 
  in 
  both 
  

   valves 
  ; 
  lateral 
  teeth 
  long 
  and 
  slightly 
  curved 
  ; 
  anterior 
  cicatrices 
  dis- 
  

   tinct 
  ; 
  posterior 
  cicatrices 
  confluent 
  ; 
  dorsal 
  cicatrices 
  situated 
  on 
  the 
  

   under 
  part 
  of 
  the 
  cardinal 
  tooth 
  ; 
  cavity 
  of 
  the 
  beaks 
  subangular 
  and 
  

   wide 
  ; 
  nacre 
  pearly 
  white 
  and 
  iridescent. 
  

  

  Remarks. 
  — 
  I 
  procured 
  two 
  opposed 
  valves 
  of 
  different 
  individuals 
  of 
  

   this 
  species, 
  which 
  nearly 
  match, 
  of 
  Mr 
  Stutchbury, 
  a 
  well 
  known 
  and 
  

  

  