﻿BIHANG 
  TILL 
  K. 
  SV. 
  VET.-AKAD. 
  HANUL. 
  BAND 
  6. 
  N:0 
  21. 
  13 
  

  

  occiirring 
  in 
  tlie 
  Arctic 
  Sea. 
  The 
  species 
  living 
  both 
  in 
  

   brackish 
  and 
  in 
  fresli 
  water 
  do 
  not 
  seem 
  to 
  follow 
  any 
  rule 
  

   as 
  to 
  their 
  relative 
  dimensions. 
  

  

  An 
  other 
  question 
  of 
  some 
  interest 
  is 
  that 
  one, 
  whether 
  

   the 
  diatomaceous 
  vegetation 
  is 
  quite 
  tlie 
  same 
  in 
  all 
  parts 
  

   of 
  the 
  Baltic. 
  From 
  the 
  Gulf 
  of 
  Bothnia 
  I 
  have 
  had 
  onlj 
  

   few 
  samples 
  for 
  examination 
  and 
  therefore 
  I 
  do 
  not 
  know 
  

   its 
  diatomaceous 
  flora 
  very 
  well, 
  but 
  in 
  the 
  slides 
  that 
  I 
  

   have 
  examined, 
  the 
  fresh 
  water 
  species 
  were 
  predominant 
  

   över 
  the 
  real 
  Baltic 
  ones. 
  Regarding 
  the 
  vegetation 
  of 
  the 
  

   rest 
  of 
  tlie 
  Baltic, 
  the 
  freshwater 
  species 
  seem 
  to 
  decrease 
  to- 
  

   wards 
  the 
  south, 
  so 
  that, 
  for 
  instance, 
  Cymbella 
  Cistula 
  Hempr., 
  

   Encyonema 
  caespitosiim 
  K., 
  Cymotopleura 
  Solea 
  Sm. 
  and 
  others 
  

   which 
  are 
  very 
  common 
  on 
  the 
  coast 
  of 
  Upland, 
  are 
  very 
  

   scarce 
  already 
  in 
  the 
  Kalmar 
  Sound 
  and 
  very 
  rare 
  on 
  the 
  

   coast 
  of 
  Skåne 
  and 
  Blekinge; 
  on 
  the 
  other 
  hand, 
  the 
  marine 
  

   forms 
  grow 
  less 
  frequent 
  from 
  the 
  soiith 
  to 
  the 
  north, 
  so 
  

   that, 
  for 
  instance, 
  Melosira 
  Borreri 
  Sm., 
  M. 
  nummnloides 
  Dillw., 
  

   Achnanthes 
  longipes 
  Lgb., 
  Licmophorae 
  a. 
  o. 
  are 
  common 
  

   on 
  the 
  coast 
  of 
  Skåne 
  and 
  Blekinge 
  but 
  scarce 
  more 
  to 
  the 
  

   north. 
  So 
  some 
  really 
  marine 
  species, 
  such 
  as 
  Navic. 
  directa 
  

   Sm. 
  and 
  N. 
  cruciformis 
  Donk., 
  are 
  found 
  only 
  in 
  the 
  south- 
  

   most 
  part 
  of 
  the 
  Baltic. 
  

  

  Of 
  the 
  synonyms 
  I 
  have 
  quoted 
  only 
  those 
  which 
  I 
  

   have 
  thought 
  necessary 
  for 
  the 
  distinct 
  indication 
  of 
  the 
  

   species, 
  and 
  those 
  which 
  are 
  used 
  in 
  papers 
  on 
  Baltic 
  dia- 
  

   töms. 
  Moreover 
  I 
  have 
  generally 
  quoted 
  the 
  work 
  that 
  I 
  

   have 
  used 
  for 
  the 
  determination 
  of 
  the 
  species. 
  

  

  