﻿8 
  PROPAGATION 
  OF 
  FRESH-WATER 
  MUSSELS. 
  

  

  DETAILS 
  OF 
  OBSERVATIONS. 
  

  

  In 
  the 
  following 
  account, 
  the 
  experiments 
  and 
  observations 
  have 
  

   been 
  described 
  under 
  the 
  name 
  of 
  each 
  species. 
  This 
  was 
  done 
  for 
  

   the 
  sake 
  of 
  clearness 
  and 
  convenience, 
  and 
  it 
  will 
  be 
  readily 
  seen 
  that 
  

   all 
  have 
  not 
  received 
  equal 
  attention. 
  I 
  have 
  followed 
  chiefly 
  the 
  

   classification 
  and 
  nomenclature 
  of 
  Simpson 
  (1900), 
  in 
  places 
  employ- 
  

   ing 
  Ortmann's 
  system, 
  in 
  which 
  case 
  it 
  is 
  so 
  indicated. 
  The 
  changes 
  

   made 
  by 
  Ortmann, 
  so 
  far 
  as 
  they 
  apply 
  to 
  the 
  forms 
  I 
  have 
  considered, 
  

   seem 
  justified. 
  These 
  are 
  based, 
  according 
  to 
  that 
  author, 
  upon 
  a 
  

   thorough 
  study 
  of 
  the 
  anatomical 
  characters 
  of 
  the 
  soft 
  parts 
  as 
  well 
  

   as 
  of 
  the 
  shell. 
  It 
  seems 
  evident 
  enough 
  that 
  a 
  continuance 
  of 
  this 
  

   kind 
  of 
  revision 
  is 
  very 
  desirable. 
  In 
  this 
  I 
  make 
  no 
  criticism 
  of 
  the 
  

   herculean 
  labors 
  of 
  Simpson, 
  whose 
  synopsis 
  has 
  removed 
  the 
  tax- 
  

   onomy 
  of 
  the 
  Naiades 
  from 
  chaos. 
  

  

  I 
  have 
  described 
  and 
  figured 
  some 
  of 
  the 
  glochidia 
  in 
  order 
  to 
  bring 
  

   out 
  features 
  not 
  previously 
  considered, 
  while 
  others 
  previously 
  pub- 
  

   lished 
  are 
  reproduced 
  in 
  order 
  to 
  show 
  all 
  on 
  the 
  same 
  scale. 
  In 
  the 
  

   dimensions 
  the 
  "height" 
  signifies 
  the 
  longest 
  axis 
  perpendicular 
  to 
  

   the 
  hinge 
  line, 
  while 
  the 
  "length" 
  is 
  the 
  longest 
  axis 
  parallel 
  to 
  the 
  

   hinge 
  fine. 
  The 
  range 
  given 
  for 
  each 
  dimension 
  is 
  the 
  extent 
  of 
  vari- 
  

   ation 
  that 
  I 
  have 
  observed. 
  The 
  greatest 
  that 
  I 
  have 
  measured 
  was 
  

   12 
  per 
  cent. 
  If 
  the 
  measurements 
  had 
  been 
  taken 
  from 
  several 
  

   broods 
  of 
  glochidia 
  from 
  different 
  localities, 
  this 
  variation 
  would 
  

   probably 
  be 
  larger. 
  

  

  Very 
  Httle 
  has 
  been 
  published 
  regarding 
  the 
  juvenile 
  stages 
  of 
  the 
  

   Quadrulas. 
  It 
  is 
  not 
  my 
  intention 
  to 
  go 
  into 
  details 
  of 
  description 
  

   here, 
  reserving 
  such 
  observations 
  for 
  a 
  later 
  paper; 
  however, 
  a 
  tew 
  

   notes 
  ai'e 
  given 
  by 
  way 
  of 
  caUing 
  attention 
  to 
  this 
  httle-known 
  stage. 
  

   I 
  regard 
  a 
  knowledge 
  of 
  these 
  as 
  necessary 
  for 
  a 
  proper 
  consideration 
  

   of 
  the 
  problems 
  connected 
  with 
  the 
  propagation 
  of 
  mussels. 
  If 
  the 
  

   suggestion 
  (Lefevre 
  and 
  Curtis, 
  1912, 
  p. 
  192) 
  that 
  propagation 
  be 
  

   carried 
  through 
  this 
  stage 
  prove 
  to 
  be 
  feasible, 
  such 
  information 
  

   would 
  be 
  indispensable. 
  Again, 
  a 
  knowledge 
  of 
  these 
  is 
  required 
  for 
  

   the 
  maintenance 
  of 
  proper 
  conditions 
  for 
  the 
  natural 
  development 
  of 
  

   mussel 
  beds. 
  From 
  the 
  few 
  observations 
  that 
  have 
  been 
  pubUshed 
  

   upon 
  juveniles 
  of 
  North 
  American 
  Unionidse 
  (Isely, 
  1911 
  ; 
  White, 
  1905 
  ; 
  

   Sterki, 
  18G1 
  a, 
  b), 
  it 
  seems 
  probable 
  that, 
  in 
  some 
  cases 
  at 
  least, 
  they 
  

   have 
  a 
  habitat 
  quite 
  different 
  from 
  the 
  adult. 
  For 
  example, 
  some 
  

   species, 
  such 
  as 
  the 
  yellow 
  sand-shell, 
  Lampsilis 
  anodontoides, 
  and 
  the 
  

   butterfly, 
  Plagiola 
  securis, 
  have 
  been 
  found 
  in 
  the 
  shallow 
  water 
  of 
  

   rapids 
  or 
  riffles 
  attached 
  to 
  stones 
  or 
  gravel 
  by 
  a 
  byssus, 
  while 
  the 
  

   adult 
  dwells 
  in 
  deep 
  water 
  on 
  a 
  mud 
  or 
  sand 
  bottom. 
  Differences 
  so 
  

   great 
  between 
  the 
  habitat 
  of 
  the 
  young 
  and 
  the 
  adult 
  would 
  be 
  im- 
  

   portant 
  considerations 
  in 
  any 
  attempt 
  to 
  raise 
  mussels 
  artificially 
  

   through 
  this 
  stage. 
  

  

  