﻿70 
  ON 
  THE 
  NAIADES, 
  

  

  Unio 
  dromas. 
  Plate 
  X. 
  fig. 
  29. 
  

  

  Testa 
  subtriangulari, 
  subobliqud, 
  gibbd, 
  irregular 
  iter 
  iransversimque 
  plicatd, 
  

   punctiunculis 
  passim 
  radiata 
  ; 
  valvulis 
  crassissi?nis 
  ; 
  natibus 
  prominentibus 
  ; 
  

   dentibus 
  cardinalibus 
  latis, 
  lateralibus 
  crassis 
  brevibusque 
  ; 
  margaritd 
  alba. 
  

  

  Shell 
  subtriangular, 
  somewhat 
  oblique, 
  hunch-backed, 
  irregularly 
  and 
  transversely- 
  

   folded, 
  with 
  dotted 
  rays 
  over 
  the 
  whole 
  disk 
  ; 
  valves 
  very 
  thick; 
  beaks 
  elevated 
  ; 
  car- 
  

   dinal 
  teeth 
  wide 
  ; 
  lateral 
  teeth 
  short 
  and 
  thick 
  ; 
  nacre 
  pearly 
  white. 
  

  

  Hab. 
  Harpeth 
  River, 
  Tennessee. 
  Professor 
  Conrad. 
  

   Hab. 
  Cumberland 
  River, 
  near 
  Nashville. 
  Professor 
  Troost. 
  

  

  My 
  Cabinet. 
  

   Cabinet 
  of 
  the 
  Academy 
  of 
  Natural 
  Sciences 
  of 
  Philadelphia. 
  

   Cabinet 
  of 
  Professor 
  Troost. 
  

   Cabinet 
  of 
  P. 
  H. 
  Nicklin. 
  

   Diam 
  1-6, 
  Length 
  1-8, 
  Breadth 
  1-9 
  inches. 
  

  

  Shell 
  subtriangular, 
  somewhat 
  oblique, 
  hunch-backed, 
  irregularly 
  

   and 
  transversely 
  folded 
  at 
  the 
  separate 
  stages 
  of 
  growth, 
  furnished 
  with 
  

   an 
  oblique 
  furrow 
  before 
  the 
  umbonial 
  slope, 
  substance 
  of 
  the 
  shell 
  

   very 
  thick 
  ; 
  beaks 
  thick 
  and 
  elevated 
  ; 
  ligament 
  short, 
  thick 
  and 
  dark 
  

   coloured; 
  umbones 
  furnished 
  with 
  a 
  hump; 
  epidermis 
  yellow, 
  with 
  

   numerous 
  dark 
  green 
  dotted 
  rays, 
  on 
  the 
  anterior 
  part 
  furnished 
  with 
  

   about 
  six 
  somewhat 
  broad 
  rays; 
  cardinal 
  tooth 
  wide 
  and 
  sulcate; 
  lateral 
  

   tooth 
  short 
  and 
  thick, 
  having 
  a 
  flat 
  plate 
  between 
  it 
  and 
  the 
  cardinal 
  

   tooth 
  ; 
  anterior 
  and 
  posterior 
  cicatrices 
  both 
  distinct 
  ; 
  dorsal 
  cicatrices 
  

   situated 
  on 
  the 
  under 
  side 
  of 
  the 
  cardinal 
  tooth 
  ; 
  cavity 
  of 
  the 
  beaks 
  

   deep 
  and 
  angulated 
  ; 
  nacre 
  pearly 
  white, 
  on 
  the 
  posterior 
  part 
  some- 
  

   times 
  golden. 
  

  

  Remarks. 
  — 
  I 
  have 
  had 
  for 
  some 
  years 
  in 
  my 
  cabinet 
  two 
  specimens 
  

   of 
  this 
  beautiful 
  and 
  curious 
  species, 
  the 
  first 
  of 
  which, 
  a 
  young 
  one, 
  I 
  

   owe 
  to 
  the 
  kindness 
  of 
  the 
  late 
  professor 
  Conrad. 
  Having 
  recently 
  

   received 
  a 
  complete 
  suite 
  from 
  professor 
  Troost, 
  I 
  have 
  perfectly 
  satis- 
  

   fied 
  myself 
  of 
  (what 
  I 
  before 
  doubted) 
  its 
  being 
  distinct 
  from 
  the 
  

   irroratus 
  (nobis). 
  The 
  manner 
  in 
  which 
  the 
  hump 
  is 
  formed 
  is 
  very 
  

   remarkable. 
  As 
  far 
  as 
  the 
  third 
  or 
  fourth 
  stage 
  of 
  growth 
  the 
  disks 
  

  

  