﻿AND 
  OTHER 
  FAMILIES. 
  73 
  

  

  Hab. 
  Harpeth 
  River, 
  Tennessee. 
  Professor 
  Troost. 
  

  

  My 
  Cabinet. 
  

  

  Cabinet 
  of 
  Professor 
  Troost, 
  Nashville. 
  

  

  Diam. 
  1*4, 
  Length 
  1-9, 
  Breadth 
  3-1 
  inches. 
  

  

  Shell 
  elliptical, 
  subangular 
  behind, 
  nearly 
  equilateral, 
  inflated, 
  trans- 
  

   verse 
  ; 
  substance 
  of 
  the 
  shell 
  rather 
  thick 
  ; 
  beaks 
  slightly 
  elevated 
  and 
  

   without 
  undulations 
  at 
  tip; 
  ligament 
  short 
  and 
  thick; 
  epidermis 
  yel- 
  

   lowish 
  with 
  irregularly 
  interrupted 
  rays 
  over 
  the 
  whole 
  disk; 
  cardinal 
  

   teeth 
  elevated, 
  double 
  in 
  the 
  left 
  valve 
  and 
  single 
  in 
  the 
  right; 
  lateral 
  

   teeth 
  enlarged 
  and 
  disposed 
  to 
  be 
  bladed 
  at 
  the 
  termination 
  ; 
  anterior 
  

   cicatrices 
  distinct; 
  posterior 
  cicatrices 
  confluent; 
  dorsal 
  cicatrices 
  situ- 
  

   ated 
  along 
  the 
  base 
  of 
  the 
  cardinal 
  tooth 
  and 
  under 
  the 
  plate 
  between 
  

   the 
  cardinal 
  and 
  lateral 
  teeth 
  ; 
  cavity 
  of 
  the 
  beaks 
  wide 
  and 
  obtusely 
  

   angulate; 
  nacre 
  pearly 
  white, 
  extending 
  only 
  far 
  enough 
  to 
  leave 
  a 
  

   broad 
  horn 
  coloured 
  border. 
  

  

  Remarks. 
  — 
  This 
  species 
  was 
  among 
  the 
  shells 
  sent 
  to 
  me 
  by 
  professor 
  

   Troost. 
  To 
  judge 
  from 
  the 
  few 
  specimens 
  I 
  have 
  seen, 
  I 
  should 
  sup- 
  

   pose 
  it 
  varied 
  much 
  from 
  age 
  as 
  well 
  as 
  locality. 
  One 
  of 
  my 
  speci- 
  

   mens 
  is 
  old 
  and 
  very 
  large, 
  scarcely 
  presenting 
  a 
  ray. 
  In 
  this 
  state 
  it 
  

   closely 
  resembles 
  the 
  U. 
  ohovatus 
  (nobis), 
  but 
  is 
  rather 
  more 
  trans- 
  

   verse. 
  The 
  younger 
  and 
  more 
  perfect 
  specimens 
  approach 
  more 
  

   closely 
  to 
  the 
  U. 
  crassus 
  (Say), 
  but 
  are 
  more 
  inflated, 
  and 
  differ 
  in 
  the 
  

   rays, 
  which 
  are 
  broken 
  into 
  irregular 
  spots, 
  not 
  entirely 
  dissimilar 
  to 
  

   the 
  plumage 
  of 
  the 
  partridge. 
  It 
  has 
  some 
  resemblance 
  to 
  the 
  U. 
  pie- 
  

   ties 
  herein 
  described, 
  but 
  is 
  not 
  compressed 
  like 
  that 
  species, 
  and 
  diners 
  

   in 
  the 
  rays. 
  In 
  some 
  specimens 
  the 
  teeth 
  are 
  disposed 
  to 
  be 
  pinkish. 
  

  

  Unio 
  Pictus. 
  Plate 
  XI. 
  fig. 
  32. 
  

  

  Testa 
  ellipticd, 
  compressd, 
  insequilaterali 
  ; 
  valvulis 
  subtenuibus 
  ; 
  natibus 
  com- 
  

   pressis 
  et 
  ad 
  apices 
  undulatis 
  ; 
  epidermide 
  luted, 
  radiis 
  tenebroso-viridibus 
  inter- 
  

   ruptis 
  ; 
  dentibus 
  cardinalibus 
  parvis 
  ; 
  lateralibus 
  longis 
  et 
  subcurvis 
  ; 
  margaritd 
  

   alba 
  et 
  iridescente. 
  

  

  VOL.. 
  V. 
  T 
  

  

  