﻿40 
  ON 
  THE 
  NAIADES, 
  

  

  Hab. 
  Alabama 
  River. 
  Judge 
  Tait. 
  

  

  My 
  Cabinet. 
  

   Diam. 
  1-1, 
  Length 
  1*5, 
  Breadth 
  1*5 
  inches. 
  

  

  Shell 
  subtriangular, 
  thick, 
  oblique, 
  depressed 
  anterior 
  to 
  umbonial 
  

   slope 
  ; 
  substance 
  of 
  the 
  shell 
  very 
  thick 
  anteriorly 
  and 
  thin 
  posteriorly 
  ; 
  

   beaks 
  very 
  thick 
  and 
  much 
  elevated 
  ; 
  epidermis 
  dark 
  brown 
  and 
  wrin- 
  

   kled 
  ; 
  cardinal 
  teeth 
  large, 
  crenate 
  and 
  deeply 
  cleft 
  in 
  the 
  left 
  valve, 
  

   and 
  emerging 
  from 
  a 
  pit 
  in 
  the 
  right 
  ; 
  lateral 
  teeth 
  thick, 
  slightly 
  curved 
  

   and 
  nearly 
  parallel 
  with 
  the 
  line 
  of 
  the 
  cardinal 
  teeth 
  ; 
  anterior 
  cica- 
  

   trices 
  distinct, 
  the 
  great 
  one 
  forming 
  a 
  deep 
  pit 
  ; 
  posterior 
  cicatrices 
  

   distinct, 
  the 
  smaller 
  one 
  being 
  placed 
  at 
  the 
  end 
  of 
  the 
  lateral 
  tooth 
  ; 
  

   dorsal 
  cicatrices 
  situated 
  on 
  the 
  plate 
  between 
  the 
  cardinal 
  and 
  lateral 
  

   teeth 
  ; 
  cavity 
  of 
  the 
  beaks 
  shallow 
  ; 
  nacre 
  pearly 
  white. 
  

  

  Remarks. 
  — 
  There 
  is 
  no 
  species 
  which 
  this 
  so 
  closely 
  resembles 
  as 
  

   the 
  scalenius 
  (Rafin.). 
  It 
  is, 
  however, 
  less 
  oblique 
  and 
  more 
  expanded 
  

   along 
  the 
  posterior 
  basal 
  margin, 
  and 
  the 
  posterior 
  margin 
  forms 
  a 
  more 
  

   obtuse 
  angle. 
  It 
  is 
  with 
  great 
  pleasure 
  I 
  name 
  it 
  after 
  my 
  friend, 
  

   Judge 
  Tait 
  of 
  Claiborne, 
  Alabama, 
  to 
  whom 
  science 
  is 
  greatly 
  indebted 
  

   for 
  his 
  exertions 
  in 
  making 
  known 
  the 
  natural 
  history 
  of 
  his 
  vicinity. 
  

  

  Unio 
  lacteolus. 
  Plate 
  VIII. 
  fig. 
  19. 
  

  

  Testd 
  ellipticd, 
  transversa, 
  insequilaterali, 
  subinfiatd; 
  valvulis 
  subcrassis 
  ; 
  nati- 
  

   bus 
  radiatis, 
  plicis 
  brevibus 
  ; 
  dentibus 
  cardinalibus 
  in 
  valvuld 
  ulrdque 
  duplicibus 
  

   longisque 
  ; 
  lateralibus 
  longis, 
  a 
  cardinalibus 
  separatis 
  ; 
  margaritd 
  lacteold. 
  

  

  Shell 
  elliptical, 
  transverse, 
  inequilateral, 
  somewhat 
  inflated 
  ; 
  valves 
  not 
  thick 
  ; 
  beaks 
  

   having 
  short 
  radiating 
  folds; 
  cardinal 
  teeth 
  long 
  and 
  double 
  in 
  both 
  valves 
  ; 
  lateral 
  

   teeth 
  long 
  and 
  separate 
  from 
  the 
  cardinal 
  teeth 
  ; 
  nacre 
  pearly 
  and 
  milk 
  white. 
  

  

  Hab. 
  Rio 
  de 
  la 
  Plata. 
  

  

  My 
  Cabinet. 
  

  

  Cabinet 
  of 
  the 
  Academy 
  of 
  Natural 
  Sciences 
  of 
  Philadelphia. 
  

  

  Cabinet 
  of 
  W. 
  Hyde. 
  

  

  Unio 
  delodonta? 
  Lam. 
  

  

  