﻿THE 
  STORY 
  OF 
  A 
  PEARL. 
  

  

  51 
  

  

  only 
  one 
  pearl, 
  four 
  had 
  two, 
  two 
  had 
  four 
  of 
  different 
  sizes. 
  

   The 
  next 
  collection 
  of 
  Mussels, 
  however, 
  and 
  which 
  exceeded 
  the 
  

   former 
  in 
  number, 
  did 
  not 
  contain 
  a 
  single 
  pearl. 
  The 
  former 
  

   series 
  came 
  from 
  a 
  curve 
  of 
  the 
  Tay, 
  which 
  has 
  always 
  been 
  rich 
  

   in 
  pearls, 
  and 
  abounds 
  in 
  Otters. 
  The 
  Otter, 
  like 
  the 
  Eacoon, 
  

   Mink, 
  and 
  Musk-Eat 
  of 
  North 
  America, 
  probably 
  preys 
  on 
  the 
  

   the 
  Mussels 
  (Jameson), 
  and 
  it 
  may 
  be 
  that 
  the 
  adult 
  stage 
  of 
  the 
  

   parasite 
  will 
  be 
  found 
  in 
  it. 
  In 
  North 
  America, 
  where 
  fresh- 
  

   water 
  Mussels 
  abound, 
  hogs 
  are 
  very 
  fond 
  of 
  them, 
  going 
  into 
  

   the 
  streams 
  when 
  low 
  and 
  rooting 
  them 
  up. 
  Crows 
  likewise 
  

   carry 
  them 
  up 
  trees, 
  and 
  drop 
  them 
  to 
  break 
  the 
  shells. 
  In 
  the 
  

   rivers 
  they 
  are 
  eaten 
  by 
  Cat-fishes. 
  

  

  In 
  order 
  to 
  test 
  the 
  frequency 
  of 
  their 
  occurrence 
  in 
  the 
  

   Common 
  Mussel 
  of 
  the 
  Eden, 
  Mr. 
  Alex. 
  Eussell, 
  M.A., 
  examined 
  

   TOO.* 
  Of 
  this 
  number 
  620 
  were 
  large 
  and 
  80 
  small 
  — 
  some 
  very 
  

   small 
  — 
  Mussels. 
  Of 
  the 
  620 
  large 
  Mussels, 
  pearls 
  were 
  found 
  in 
  

   280 
  — 
  that 
  is 
  to 
  say, 
  340 
  had 
  no 
  pearls 
  ; 
  and 
  of 
  the 
  80 
  small 
  

   Mussels, 
  20 
  had 
  pearls, 
  and 
  60 
  were 
  devoid 
  of 
  them. 
  In 
  dealing 
  

   with 
  the 
  pearl 
  bearing 
  forms 
  both 
  large 
  and 
  small, 
  and 
  which 
  

   thus 
  number 
  300, 
  the 
  following 
  table 
  gives 
  the 
  precise 
  number 
  

   of 
  pearls 
  in 
  each 
  series, 
  as 
  well 
  as 
  the 
  totals 
  ;— 
  - 
  

  

  No. 
  of 
  Pearls. 
  

  

  1 
  2 
  

  

  3 
  

  

  4 
  

  

  5 
  

  

  6 
  

  

  7 
  

  

  8 
  or 
  more 
  Pearls. 
  

  

  Totals. 
  

  

  Large 
  Mussels 
  

   Small 
  ,, 
  

  

  136 
  67 
  

   12 
  — 
  

  

  31 
  

   5 
  

  

  15 
  

  

  7 
  

   1 
  

  

  14 
  

  

  3 
  

  

  7 
  

  

  2 
  (12 
  pearls) 
  

  

  280 
  

   20 
  

  

  Totals 
  

  

  148 
  67 
  

  

  36 
  

  

  15 
  

  

  8 
  

  

  14 
  

  

  3 
  

  

  9 
  

  

  300 
  

  

  

  

  The 
  proportion 
  of 
  the 
  300 
  pearl-bearing 
  Mussels 
  to 
  the 
  total 
  

   number 
  (700) 
  is 
  thus 
  42'8 
  per 
  cent., 
  but 
  if 
  the 
  large 
  Mussels 
  

   alone 
  are 
  considered, 
  the 
  proportion 
  is 
  higher, 
  viz. 
  45'1 
  per 
  cent., 
  

   which 
  indicates 
  that 
  the 
  Common 
  Mussel 
  more 
  or 
  less 
  follows 
  

   the 
  same 
  law 
  as 
  the 
  Pearl-Oyster, 
  viz. 
  that 
  the 
  older 
  forms 
  pro- 
  

   duce 
  most 
  pearls. 
  Indeed, 
  the 
  number 
  of 
  pearls 
  in 
  the 
  very 
  

   small 
  Mussels 
  at 
  St. 
  Andrews 
  is 
  noteworthy, 
  and 
  may 
  be 
  explained 
  

   by 
  the 
  fact 
  that 
  the 
  very 
  small 
  are 
  not 
  necessarily 
  young 
  Mussels, 
  

   * 
  ' 
  Ann. 
  Nat, 
  Hist.' 
  ser. 
  7, 
  p. 
  549, 
  June, 
  1903. 
  

  

  