﻿AND 
  OTHER 
  FAMILIES. 
  87 
  

  

  same 
  opinion) 
  to 
  be 
  the 
  Mya 
  margaritifera 
  of 
  Linnaeus. 
  It 
  has 
  all 
  

   the 
  characters 
  of 
  this 
  species, 
  with 
  the 
  exception 
  of 
  the 
  addition 
  of 
  the 
  

   thick 
  lateral 
  tooth, 
  which 
  our 
  author 
  does 
  not 
  describe, 
  hut 
  could 
  

   scarcely 
  have 
  failed 
  to 
  have 
  observed. 
  Being 
  possessed 
  of 
  this 
  tooth, 
  

   it 
  is 
  of 
  course 
  a 
  true 
  Unio. 
  Pfeiffer 
  describes 
  an 
  old 
  margaritifera 
  

   under 
  the 
  name 
  of 
  sinuata. 
  He 
  says 
  " 
  dente 
  cardinali 
  valido, 
  subcon- 
  

   ico, 
  laterali 
  nullo." 
  In 
  the 
  north 
  of 
  Europe, 
  (for 
  the 
  sinuata 
  exists 
  

   only 
  in 
  the 
  south) 
  he 
  had 
  not, 
  perhaps, 
  like 
  ourselves, 
  until 
  recently, 
  an 
  

   opportunity 
  of 
  examining 
  the 
  true 
  sinuata 
  of 
  Lamarck. 
  

  

  Unio 
  elongata. 
  This 
  is 
  the 
  true 
  Mya 
  margaritifera 
  of 
  Linnaeus 
  

   and 
  other 
  authors. 
  The 
  Masmodonta 
  arcuata 
  of 
  Barnes 
  is 
  its 
  ana- 
  

   logue 
  in 
  this 
  country. 
  It 
  inhabits 
  the 
  north 
  of 
  Europe, 
  lake 
  Ladoga, 
  

   Norway, 
  &c. 
  

  

  Unio 
  crassidens. 
  The 
  specimen 
  quoted 
  from 
  Lamarck's 
  own 
  col- 
  

   lection, 
  which 
  is 
  now 
  in 
  the 
  possession 
  of 
  the 
  Duke 
  de 
  Rivoli, 
  is 
  the 
  

   cuneatus 
  of 
  Barnes. 
  Var. 
  a 
  is 
  the 
  trapezoides 
  (nobis), 
  a 
  shell 
  very 
  

   different 
  in 
  its 
  general 
  characters, 
  being 
  always 
  folded. 
  Crassidens 
  

   therefore 
  has 
  precedence 
  of 
  cuneatus. 
  

  

  Unio 
  Peruviana. 
  This 
  is 
  the 
  plicatus 
  of 
  Le 
  Sueur, 
  now 
  so 
  well 
  

   known 
  in 
  all 
  our 
  collections. 
  Valenciennes 
  says, 
  Dombey's 
  shell 
  re- 
  

   mains 
  in 
  the 
  museum, 
  and 
  that 
  Lamarck 
  described 
  a 
  North 
  American 
  

   shell 
  in 
  error. 
  The 
  figure 
  referred 
  to 
  by 
  Lamarck, 
  in 
  the 
  Ency. 
  

   Methodique, 
  is 
  certainly 
  the 
  well 
  known 
  plicatus 
  of 
  our 
  western 
  waters. 
  

  

  Unio 
  purpurata. 
  Lamarck 
  supposed 
  the 
  specimens 
  he 
  examined 
  

   to 
  have 
  come 
  from 
  Africa. 
  I 
  examined 
  the 
  specimen 
  cited, 
  in 
  the 
  

   Duke 
  de 
  Rivoli's 
  collection, 
  as 
  well, 
  also, 
  one 
  in 
  that 
  of 
  Baron 
  de 
  

   Ferussac. 
  These 
  specimens 
  have 
  been 
  polished, 
  and 
  have, 
  most 
  pro- 
  

   bably, 
  been 
  in 
  the 
  cabinet 
  of 
  Paris 
  for 
  twenty 
  or 
  thirty 
  years 
  ; 
  for, 
  few 
  

   Uniones 
  were 
  admitted 
  into 
  the 
  cabinet, 
  at 
  that 
  time, 
  without 
  the 
  loss 
  

   of 
  their 
  superficial 
  protection. 
  It 
  is 
  the 
  ater 
  (nobis), 
  and, 
  most 
  pro- 
  

   bably, 
  was 
  taken 
  from 
  the 
  neighbourhood 
  of 
  New 
  Orleans, 
  while 
  in 
  

   possession 
  of 
  the 
  French. 
  The 
  specimen 
  described 
  and 
  figured 
  in 
  one 
  

   of 
  my 
  former 
  memoirs, 
  came 
  from 
  Port 
  Gibson, 
  below 
  Natchez 
  ; 
  and 
  I 
  

   subsequently 
  received 
  some 
  from 
  the 
  vicinity 
  of 
  New 
  Orleans 
  and 
  from 
  

   Claiborne, 
  Alabama. 
  I 
  therefore, 
  willingly 
  yield 
  the 
  name 
  to 
  Lamarck.* 
  

  

  * 
  In 
  the 
  " 
  American 
  Conchology," 
  No. 
  V., 
  Mr 
  Say 
  re-describes 
  and 
  re-figures 
  the 
  Unio 
  

  

  