﻿20 
  S. 
  A. 
  TULLBERG, 
  GRAPTOLITES 
  DESCRIBED 
  BY 
  IIISINGEU. 
  

  

  Dictyonema 
  flabelliforme 
  Eichw. 
  

  

  Plate 
  III, 
  lig. 
  1—4. 
  

  

  Bromell, 
  »Musci 
  ramosi 
  capillatnenta 
  nigra:?. 
  Lithographiae 
  sue- 
  

   cante, 
  specimen 
  secundnm. 
  Articuliis 
  I, 
  N:o 
  1, 
  1727. 
  — 
  Gorgonia 
  fla- 
  

   helUformis 
  EiCHWALD, 
  Schichtensyst., 
  Russlands, 
  18iO. 
  — 
  Phyllograpta, 
  

   AngelijS^, 
  Palasont. 
  Scand. 
  I, 
  p. 
  IV, 
  1854. 
  — 
  Fenestella 
  socialis 
  Salter 
  

   according 
  to 
  Kjeeulf, 
  Ueber 
  die 
  Geologie 
  des 
  siidlichen 
  Norwegens, 
  p. 
  79, 
  

   1857. 
  — 
  Rhahdinopora 
  flahdUfortnis 
  Eichwald, 
  Lethsea 
  rossica 
  I, 
  i, 
  p. 
  369, 
  

   1862. 
  — 
  Dictyomma 
  Hisingeri 
  Göppeet, 
  Ueber 
  die 
  fossile 
  Flora 
  etc. 
  

   1862, 
  p. 
  455, 
  tab. 
  XXXVI, 
  ilg. 
  6— 
  -11, 
  tab. 
  XL 
  V, 
  fig. 
  3, 
  4. 
  — 
  D. 
  Jiahelli- 
  

   formis 
  TÖRNQUIST, 
  Fågelsångstraktens 
  imdersilur. 
  lager, 
  Lund, 
  1865, 
  p. 
  22. 
  — 
  

   Ceramites 
  lUsingeri 
  Liebm., 
  Hamb. 
  lit. 
  u. 
  krit. 
  Blätter 
  1848, 
  N. 
  12. 
  — 
  

   The 
  name 
  Dictyonema 
  was 
  already 
  published 
  by 
  Hall 
  1851 
  in 
  Paleont. 
  

   New 
  York, 
  Vol. 
  II, 
  page 
  174. 
  

  

  The 
  liydrosoma 
  forms 
  by 
  its 
  braBches 
  a 
  flat, 
  extended 
  

   disc, 
  growing 
  out 
  from 
  a 
  long 
  and 
  narrow 
  sicula, 
  which 
  in 
  

   its 
  distal 
  part 
  divides 
  into 
  two 
  branches, 
  which 
  immediately 
  

   again 
  give 
  ofF 
  new 
  branches; 
  by 
  reiterated 
  dichotomy 
  a 
  

   multitude 
  of 
  subparallel 
  branches 
  appear, 
  connected 
  by 
  fine 
  

   chitinous 
  filaments, 
  which 
  in 
  short 
  almost 
  regular, 
  distances 
  

   are 
  stretched 
  out 
  nearly 
  horizontally 
  from 
  one 
  branch 
  to 
  

   another. 
  Every 
  branch 
  bears, 
  as 
  it 
  appears, 
  two 
  series 
  of 
  

   hydrothecae, 
  alternatiug 
  with 
  each 
  other. 
  The 
  horizontal 
  

   chitinous 
  threads 
  seem 
  always 
  to 
  arise 
  from 
  the 
  apertural 
  

   edge 
  of 
  a 
  hydrotheca; 
  in 
  certain 
  forms 
  there 
  is 
  seen 
  one 
  thread 
  

   extending 
  from 
  every 
  hydrotheca 
  — 
  this 
  is 
  not 
  the 
  case 
  with 
  

   Hisinger's 
  specimen 
  — 
  ; 
  on 
  others 
  from 
  only 
  oné 
  of 
  ii<;o 
  thecas, 
  

   which 
  seems 
  to 
  be 
  most 
  common 
  for 
  examples 
  from 
  Fågel- 
  

   sång 
  and 
  for 
  that 
  from 
  the 
  Piperviken 
  in 
  Norway; 
  on 
  other 
  

   specimens 
  again, 
  only 
  every 
  third 
  or 
  fourth 
  theca 
  bears 
  one 
  

   chitinous 
  thread 
  extending 
  to 
  the 
  nearest 
  branch. 
  This 
  has 
  

   been 
  observed 
  on 
  several 
  specimens 
  from 
  Aby 
  in 
  Ostro- 
  

   gothia, 
  which 
  are 
  preserved 
  in 
  the 
  State-Museum 
  at 
  Stockholm. 
  

   The 
  hydrothecae 
  are 
  to 
  be 
  observed 
  only 
  on 
  well 
  preserved 
  

   specimens, 
  and 
  on 
  these 
  with 
  difficulty; 
  they 
  seem 
  to 
  form 
  

   elongated 
  tubes, 
  with 
  the 
  apertural-edge 
  scarcely 
  projecting 
  for- 
  

   ward; 
  sometimes 
  there 
  are 
  to 
  be 
  seen 
  long 
  impressed 
  lines, 
  

   indicating 
  interiör 
  septa. 
  On 
  a 
  length 
  of 
  10 
  mm. 
  there 
  are 
  

   10 
  — 
  15 
  hydrothecae. 
  There 
  are 
  no 
  traces 
  of 
  a 
  virgula. 
  

  

  