﻿BIHANG 
  TILL 
  K. 
  SV. 
  VET.-AKAD. 
  HANDL. 
  BAND 
  6. 
  N:0 
  21. 
  9 
  

  

  curvata 
  Gkun., 
  Synedra 
  piilchella 
  and 
  affinis 
  K. 
  Schwårz 
  ^) 
  

   also 
  observes 
  that 
  all 
  bottom 
  specimens, 
  examined 
  by 
  bim, 
  

   were 
  almost 
  destitute 
  of 
  .diatoms, 
  and 
  J. 
  H. 
  L. 
  Flögel 
  ^) 
  

   says 
  tliat 
  the 
  bottom 
  specimens 
  contained 
  almost 
  no 
  valves, 
  

   and 
  tbose 
  tbat 
  were 
  fonnd 
  imbedded 
  in 
  tbem, 
  did 
  not 
  belong 
  

   to 
  the 
  species 
  abundantly 
  occurring 
  on 
  the 
  shores. 
  A 
  similar 
  

   observation 
  is 
  also 
  made 
  by 
  Geegory 
  ^) 
  who 
  supposes 
  that 
  

   the 
  species 
  which 
  are 
  mentioned 
  as 
  occurring 
  at 
  great 
  depths 
  

   in 
  the 
  Atlantic 
  and 
  the 
  Pacific 
  Ocean, 
  have 
  not 
  lived 
  near 
  

   the 
  bottom 
  but 
  have 
  sunk 
  down 
  after 
  death. 
  In 
  Cl. 
  & 
  Moll. 
  

   Diat. 
  jSF;o 
  45 
  on 
  the 
  contrary 
  it 
  is 
  said 
  that 
  Epithemia 
  turgida 
  

   Bhb. 
  and 
  Rhabdonema 
  minutum 
  were 
  found 
  in 
  the 
  Baltic 
  

   on 
  Conferva 
  Aegagropila 
  at 
  a 
  depth 
  of 
  150 
  fathoms, 
  — 
  yet 
  

   it 
  is 
  not 
  expressly, 
  said, 
  that 
  they 
  did 
  live 
  at 
  that 
  depth. 
  

   Also 
  Flögel 
  ^) 
  says 
  that 
  Paralia 
  marina 
  Sm. 
  seems 
  to 
  live 
  

   in 
  the 
  deepest 
  regions. 
  

  

  The 
  diatoms, 
  living 
  free 
  in 
  the 
  open 
  sea 
  near 
  the 
  surface, 
  

   seem 
  to 
  occiir 
  comparatively 
  sparingly, 
  as 
  could 
  also 
  be 
  

   supposed 
  from 
  their 
  scarceness 
  in 
  the 
  bottom 
  mud. 
  Richest 
  

   in 
  diatoms 
  I 
  always 
  found 
  shallow 
  bays, 
  — 
  1 
  — 
  2 
  feet 
  deep, 
  — 
  

   open 
  to 
  the 
  sunshine 
  but 
  protected 
  from 
  winds 
  and 
  waves. 
  

   Bays 
  which 
  answer 
  these 
  conditions, 
  and 
  which 
  are 
  qu^ite 
  or 
  

   nearly 
  cut 
  off 
  from 
  open 
  connection 
  with 
  the 
  sea, 
  and 
  thus 
  

   have 
  a 
  water, 
  quite 
  fresh 
  to 
  the 
  taste 
  °), 
  — 
  often 
  have 
  a 
  

   very 
  rich 
  vegetation 
  of 
  Diatoms, 
  which 
  there, 
  together 
  with 
  

   smaller 
  green 
  algae 
  and 
  rests 
  of 
  lower, 
  microscopical 
  animals, 
  

   form 
  a 
  layer, 
  often 
  several 
  feet 
  deep, 
  which, 
  on 
  the 
  surface, 
  

   consists 
  of 
  still 
  living 
  algae 
  and 
  animals. 
  According 
  to 
  the 
  

   relative 
  quantities 
  of 
  the 
  diatoras 
  and 
  the 
  green 
  algae 
  that 
  

   compose 
  such 
  a 
  layer, 
  the 
  putrifaction 
  goes 
  faster 
  or 
  slower. 
  

   If 
  the 
  main 
  part 
  consists 
  of 
  diatoms, 
  these 
  give 
  the 
  mäss 
  a 
  

  

  ') 
  Hedwigia 
  1873 
  p. 
  49. 
  

  

  2) 
  Ostsee-Exp. 
  1871, 
  p. 
  85. 
  

  

  3) 
  Greg. 
  Clyde, 
  p. 
  

  

  *) 
  Ostsee 
  Exp. 
  1871, 
  p. 
  87. 
  

  

  5) 
  I 
  have 
  observed 
  and 
  examined 
  such 
  ^ays 
  with 
  quite 
  fresh 
  water 
  but 
  

   containing 
  a 
  diatomaceous 
  flora 
  of 
  brackisch 
  habitus 
  on 
  the 
  south 
  side 
  

   of 
  Rådmansö, 
  Upland, 
  where 
  they 
  are 
  called 
  »mar», 
  and 
  at 
  Stansvik 
  near 
  

   Helsingfors. 
  They 
  seem 
  to 
  me 
  to 
  show 
  how 
  many 
  swedish 
  peatmosses 
  

   have 
  originated: 
  a 
  shallow 
  little 
  bay 
  has 
  been 
  cut 
  ofE 
  from 
  connection 
  

   with 
  the 
  sea, 
  its 
  water 
  has 
  become 
  fresh, 
  brackish 
  water 
  diatoms 
  and 
  

   other 
  microscopical 
  plants 
  and 
  animals 
  have 
  formed 
  silt, 
  — 
  when 
  the 
  

   silt 
  nearly 
  filled 
  up 
  the 
  basin, 
  Sphagnum 
  and 
  other 
  higher 
  plants 
  have 
  

   begun 
  to 
  grow 
  there 
  and 
  have 
  formed 
  peat. 
  

  

  