﻿GROWTH 
  AND 
  MIGRATION 
  OF 
  FRESH-WATER 
  MUSSELS. 
  23 
  

  

  ISELY, 
  F. 
  B. 
  

  

  1911. 
  Preliminary 
  note 
  on 
  the 
  ecology 
  of 
  the 
  early 
  juvenile 
  life 
  of 
  the 
  Unionidae. 
  

   Ibid., 
  vol. 
  XX, 
  p. 
  77-80. 
  

   Israel, 
  W. 
  

  

  1909. 
  Uber 
  die 
  Najadeen 
  des 
  Mittelelbegebietes. 
  51 
  u. 
  52. 
  Jahresberichte 
  der 
  

  

  Gesellschaft 
  von 
  Freunden 
  der 
  Naturwissenschaften 
  in 
  Gera, 
  Reuss., 
  

   p. 
  1-38. 
  

  

  1910. 
  Die 
  Najadeen 
  des 
  Weidagebeites. 
  Beitrage 
  zur 
  Kenntniss 
  der 
  Mitteleuro- 
  

  

  poischen 
  Najaden. 
  Beilage 
  zum 
  nachrichtsblatt 
  der 
  deutschen 
  malako- 
  

   zoologischen 
  Gesellschaft, 
  p. 
  49-56. 
  

  

  1911. 
  Najadologische 
  Miscellen. 
  Nachrichtsblatt 
  der 
  deutschen 
  malakozoolo- 
  

  

  gischen 
  Gesellschaft, 
  p. 
  10-17. 
  

   Lefevre, 
  G., 
  and 
  Curtis, 
  W. 
  C. 
  

  

  1908. 
  Experiments 
  in 
  the 
  artificial 
  propagation 
  of 
  fresh-water 
  mussels. 
  Pro- 
  

   ceedings 
  of 
  the 
  Fourth 
  International 
  Fishery 
  Congress 
  (Washington), 
  

   Bulletin 
  of 
  the 
  Bureau 
  of 
  Fisheries, 
  vol. 
  xxviii, 
  p. 
  617-626. 
  

  

  1910a; 
  Reproduction 
  and 
  parasitism 
  in 
  the 
  Unionidse. 
  Journal 
  of 
  Experimental 
  

   Zoology, 
  vol. 
  9, 
  p. 
  79-115, 
  5 
  pi. 
  

  

  1910b. 
  Studies 
  on 
  the 
  reproduction 
  and 
  artificial 
  propagation 
  of 
  fresh-water 
  mus- 
  

   sels. 
  Bulletin 
  of 
  the 
  Bureau 
  of 
  Fisheries, 
  vol. 
  xxx, 
  p. 
  105-201, 
  pi. 
  

  

  VI-XVII. 
  

  

  EXPLANATION 
  OF 
  PLATES. 
  

  

  All 
  photographs 
  are 
  about 
  natural 
  size. 
  For 
  actual 
  measurements 
  see 
  tables. 
  As 
  

   already 
  explained 
  (pp. 
  10, 
  11, 
  and 
  15), 
  tags 
  were 
  fastened 
  on 
  with 
  a 
  small 
  copper 
  

   wire 
  passed 
  through 
  a 
  small 
  hole 
  made 
  about 
  2 
  mm. 
  from 
  the 
  edge 
  of 
  the 
  shell, 
  usu- 
  

   ally 
  along 
  the 
  edge 
  of 
  the 
  posterior 
  umboidal 
  ridge, 
  x 
  marks 
  the 
  tagging 
  ring, 
  i. 
  e., 
  

   the 
  ring 
  formed 
  when 
  the 
  specimen 
  was 
  marked 
  and 
  measured. 
  This" 
  ring 
  was 
  

   formed 
  without 
  exception 
  in 
  all 
  specimens 
  handled 
  and 
  thus 
  marks 
  the 
  diameter 
  of 
  

   the 
  mussel 
  at 
  the 
  time 
  of 
  tagging 
  and 
  making 
  initial 
  records; 
  x^, 
  rest 
  rings 
  formed 
  by 
  

   natural 
  processes 
  between 
  tagging 
  time 
  and 
  reclaiming 
  of 
  specimen; 
  o, 
  shadow 
  line 
  

   due 
  to 
  a 
  ridge 
  on 
  the 
  valve 
  and 
  in 
  photographic 
  cuts 
  may 
  be 
  mistaken 
  for 
  a 
  rest 
  ring. 
  

  

  Plate 
  I. 
  

  

  Specimen 
  H, 
  Lampsilis 
  gracilis 
  (table 
  8), 
  shows 
  34 
  mm. 
  growth 
  in 
  length 
  in 
  15 
  months 
  

   (June, 
  1910, 
  to 
  Sept., 
  1911); 
  x 
  marks 
  the 
  rest 
  ring 
  formed 
  when 
  the 
  specimen 
  was 
  

   marked 
  and 
  measured; 
  x^ 
  is 
  probably 
  the 
  1910-11 
  winter 
  rest 
  ring; 
  o, 
  shadow 
  line. 
  

  

  Specimen 
  323, 
  Quadrula 
  undulata 
  (table 
  1), 
  shows 
  17 
  mm. 
  increase 
  in 
  one 
  year's 
  

   growth 
  (June, 
  1910, 
  to 
  June, 
  1911). 
  A 
  new 
  ring 
  appears 
  at 
  x^ 
  near 
  the 
  margin. 
  Notice 
  

   the 
  two 
  rings, 
  y^ 
  and 
  y'^, 
  near 
  together, 
  formed 
  before 
  the 
  specimen 
  was 
  tagged. 
  

  

  Specimen 
  281, 
  Quadrula 
  undulata 
  (table 
  8), 
  shows 
  25 
  mm. 
  growth 
  in 
  15 
  months 
  

   (June, 
  1910, 
  to 
  Sept., 
  1911); 
  x^ 
  is 
  probably 
  the 
  winter 
  rest 
  ring. 
  

  

  Plate 
  II. 
  

  

  Specimen 
  355, 
  Quadrula 
  rubiginosa 
  (table 
  2), 
  shows 
  6 
  mm. 
  increase 
  in 
  15 
  months 
  

   (June, 
  1910, 
  to 
  Sept., 
  1911) 
  in 
  a 
  mature 
  slow-growing 
  species. 
  No 
  evidence 
  of 
  rest 
  

   rings 
  beyond 
  x. 
  

  

  Specimen 
  349, 
  Quadrula 
  pustulosa 
  (table 
  1), 
  shows 
  10 
  mm. 
  increase 
  in 
  one 
  year 
  

   (June, 
  1910, 
  to 
  June, 
  1911). 
  A 
  rest 
  ring, 
  not 
  well 
  brought 
  out 
  by 
  the 
  plate 
  figure, 
  

   shows 
  very 
  near 
  the 
  margin; 
  o, 
  on 
  the 
  anterior 
  slope, 
  is 
  a 
  shadow 
  line. 
  

  

  Specimen 
  564, 
  Quadrula 
  lachrymosa 
  (table 
  8), 
  shows 
  19 
  mm. 
  increase 
  in 
  length 
  in 
  

   15 
  months 
  (June, 
  1910, 
  to 
  Sept., 
  1911). 
  Tag 
  pulled 
  off 
  (t) 
  after 
  specimen 
  was 
  reclaimed. 
  

  

  Specimen 
  413 
  (table 
  8), 
  shows 
  16 
  mm. 
  increase 
  in 
  one 
  year 
  (June, 
  1910, 
  to 
  June, 
  

   1911). 
  Two 
  rest 
  rings, 
  x\ 
  x^, 
  in 
  addition 
  to 
  the 
  regular, 
  x, 
  formed 
  at 
  the 
  time 
  of 
  tagging. 
  

   If 
  we 
  count 
  the 
  one 
  at 
  the 
  tagging 
  line 
  we 
  have 
  three 
  rest 
  rings 
  for 
  one 
  year. 
  

  

  