﻿BIHANG 
  TILL 
  K. 
  SV. 
  VET.-AKAD. 
  HANDL. 
  BAND. 
  6. 
  N:0 
  21. 
  15 
  

  

  C. 
  pygmaea 
  K. 
  

  

  C. 
  oceanica 
  K. 
  

  

  C. 
  denudata 
  K. 
  

  

  C. 
  depressa 
  K. 
  

  

  C. 
  maro-inata 
  K. 
  

  

  C. 
  mediterranea 
  K. 
  

  

  C. 
  peruviana 
  K. 
  

  

  C. 
  baltica 
  ScHUM. 
  

  

  C. 
  tenera 
  Schum. 
  

  

  As 
  far 
  as 
  can 
  be 
  decided 
  from 
  KiJTZiNGS 
  small 
  figures, 
  

   Bac. 
  Fl. 
  5, 
  flgs. 
  VI 
  and 
  VIII, 
  it 
  seems 
  as 
  might 
  C. 
  pygmaea, 
  

   marginata 
  and 
  depressa 
  only 
  be 
  forms 
  of 
  C. 
  Placentula 
  or 
  

   C. 
  Pediculus, 
  C. 
  peruviana 
  and 
  C. 
  mediterranea 
  forms 
  of 
  

   C. 
  Scutellum. 
  C. 
  oceanica 
  K. 
  is 
  perliaps 
  identic 
  witli 
  my 
  

   O. 
  Placentula 
  var 
  baltica; 
  the 
  same 
  seems 
  tlie 
  case 
  be 
  with 
  

   C. 
  tenera 
  Schum., 
  C. 
  baltica 
  Schum. 
  is 
  quite 
  unknown 
  to 
  

   me. 
  Perliaps 
  it 
  is 
  a 
  small 
  form 
  of 
  N. 
  elliptica 
  K. 
  

  

  Fam. 
  Mastogloiacese. 
  

  

  Mastogloia 
  Thw. 
  

  

  M. 
  lanceolata 
  Thw. 
  

  

  This 
  species 
  seems 
  to 
  be 
  very 
  slightly 
  different 
  from 
  

   M. 
  Smitliii 
  Thw., 
  and 
  those 
  two 
  forms 
  seem 
  also 
  to 
  be 
  con- 
  

   founded 
  or 
  not 
  quite 
  well 
  distinguished 
  from 
  eacb 
  other 
  by 
  

   most 
  authors. 
  The 
  figs. 
  340 
  and 
  341 
  in 
  Smith 
  Syn. 
  Pl. 
  LIV 
  

   seem 
  to 
  represent 
  the 
  same 
  species. 
  According 
  to 
  Geunow-*) 
  

   the 
  difference 
  between 
  the 
  freshwater 
  species 
  M. 
  Smithii 
  Thw. 
  

   and 
  the 
  marine 
  M. 
  lanceolata 
  Thw. 
  is, 
  that 
  in 
  the 
  former 
  

   the 
  central 
  nodule 
  is 
  dilated 
  to 
  the 
  sides, 
  else 
  they 
  are 
  

   »iiberaus 
  ähnlich». 
  This 
  does 
  not 
  agree 
  with 
  the 
  figs. 
  13 
  and 
  

   14, 
  Plate 
  IV, 
  in 
  Vän 
  Heurcks 
  Synopsis 
  nor 
  with 
  the 
  speci- 
  

   mens 
  of 
  M. 
  Smithii 
  in 
  Cl. 
  & 
  Moll. 
  Diat. 
  N:o 
  86, 
  if 
  the 
  

   dilated 
  nodule 
  does 
  not 
  signify 
  the 
  unstriated 
  area 
  that 
  

   generally 
  surrounds 
  the 
  central 
  nodule. 
  According 
  to 
  Van 
  

   Heurcks 
  Synopsis 
  the 
  main 
  difference 
  between 
  the 
  two 
  forms 
  

   seems 
  to 
  be, 
  that 
  M. 
  lanceolata 
  has 
  its 
  transversal 
  striae 
  

   quite 
  parallel, 
  M. 
  Smithii, 
  on 
  the 
  contrary, 
  has 
  them 
  radiating. 
  

   In 
  the 
  Baltic 
  two 
  forms 
  occur, 
  distinguished 
  from 
  each 
  other 
  

   only 
  by 
  the 
  difference 
  in 
  outline; 
  in 
  both 
  the 
  striae 
  are 
  

  

  ') 
  Geun. 
  Verh. 
  Wien 
  1860, 
  p. 
  575, 
  576. 
  

  

  