﻿14 
  S. 
  A. 
  TULLBERG, 
  GRAPTOLITES 
  DESCRIBED 
  BY 
  HISINGER. 
  

  

  Monograptus 
  convolutus. 
  His. 
  

  

  Plate 
  II, 
  fig. 
  13—16. 
  

  

  Prionottis 
  convoluUis 
  His. 
  1. 
  c. 
  — 
  Mon. 
  oonvolutus 
  var. 
  d. 
  sjnralis 
  Lap. 
  

   WORTH, 
  On 
  Scottish 
  Monograptidae, 
  plate 
  XIII, 
  fig. 
  49; 
  Geol. 
  Mag. 
  1876 
  

   — 
  Bastrites 
  2JS'>'S(/rmus 
  Credner, 
  Blemente 
  der 
  Geologis, 
  3:e 
  ed., 
  fig. 
  12.5. 
  

   p. 
  392. 
  — 
  RÖMEE, 
  Lethaea 
  geoguostica. 
  Ed. 
  1876, 
  Taf 
  . 
  III, 
  fig. 
  8. 
  — 
  Gastri- 
  

   des 
  Pfaff, 
  Grundriss 
  der 
  Geologie, 
  p. 
  245, 
  fig. 
  124. 
  — 
  NoN 
  Monoprion 
  

   oonvolutus 
  Barrande, 
  Grapt. 
  de 
  BoTiéme, 
  nec 
  Monograptus 
  convolntvs 
  

   Geinitz, 
  Die 
  Graptolithen. 
  

  

  Hydrosoma 
  long, 
  convoluted 
  in 
  one 
  flat 
  spiral; 
  the 
  pro- 
  

   ximal 
  part 
  forming 
  several 
  concentric 
  spirals; 
  the 
  distal 
  

   part 
  is 
  less 
  arcuate; 
  any 
  twistiag 
  of 
  tlie 
  axis 
  has 
  not 
  been 
  

   plainly 
  observed, 
  but 
  that 
  it 
  may 
  exist, 
  is 
  shown 
  by 
  frag- 
  

   ments, 
  which 
  liave 
  the 
  hydrotliecae 
  placed 
  on 
  the 
  concave 
  

   margin; 
  on 
  the 
  proximal 
  part 
  they 
  are 
  always 
  placed 
  on 
  the 
  

   convex 
  side. 
  The 
  hydrothecae 
  are 
  scarcely 
  in 
  contact 
  with 
  

   each 
  other; 
  they 
  are 
  free, 
  rectangularly 
  projecting 
  tubes, 
  

   sharply 
  pointed 
  and 
  having 
  the 
  aperture 
  directed 
  downwards, 
  

   as 
  it 
  appears. 
  On 
  a 
  length 
  of 
  10 
  mm. 
  there 
  are 
  10 
  hydro- 
  

   thecae 
  on 
  the 
  proximal, 
  and 
  8 
  on 
  the 
  distal 
  portion. 
  The 
  

   common 
  canal 
  is 
  very 
  narrow, 
  particularly 
  in 
  the 
  proximal 
  

   portion 
  ; 
  the 
  virgula 
  is 
  plainly 
  visible 
  on 
  the 
  fully 
  developed 
  part. 
  

  

  Hisinger's 
  type 
  specimen 
  is 
  vevj 
  like 
  Rastrites 
  peregrimm, 
  

   but 
  if 
  complete 
  specimens 
  are 
  procurable, 
  in 
  which 
  the 
  

   distal 
  part 
  is 
  developed, 
  it 
  appears 
  at 
  once 
  that 
  the 
  species 
  

   is 
  a 
  Monograptus; 
  the 
  hydrothecae 
  are 
  more 
  triangulär 
  and 
  

   feebly 
  curved, 
  with 
  the 
  superior 
  margin 
  convex. 
  

  

  The 
  name 
  of 
  M. 
  spiralis 
  for 
  this 
  species 
  is 
  at 
  any 
  råte 
  

   unsuitable, 
  as 
  Geinitz 
  has 
  given 
  this 
  name 
  to 
  a 
  very 
  different 
  

   species 
  of 
  Gala 
  age, 
  and 
  which 
  moreover 
  may 
  be 
  a 
  Cyr- 
  

   tograptus. 
  To 
  cover 
  such 
  species 
  as 
  M. 
  communis 
  and 
  M. 
  

   proteus 
  with 
  Hisingers 
  denomination 
  M. 
  convolutus 
  is, 
  I 
  think 
  

   improper; 
  for 
  these 
  forms 
  seem 
  to 
  keep 
  themselves 
  constant 
  

   and 
  different 
  from 
  M. 
  convolutus. 
  

  

  This 
  species 
  occurs, 
  not 
  only 
  at 
  Furudal 
  in 
  Dalecarlia, 
  

   but 
  at 
  Kongslena 
  in 
  Vestrogothia, 
  at 
  Köstånga, 
  and 
  at 
  other 
  

   localities 
  in 
  Scania, 
  and 
  also 
  in 
  England. 
  

  

  