﻿206 
  

  

  MISS 
  G. 
  L. 
  ELLES 
  ON 
  THE 
  STLBGESTEBA 
  [May 
  1 
  897. 
  

  

  it 
  varies 
  from 
  5° 
  to 
  10°. 
  The 
  thecse 
  are 
  but 
  very 
  slightly 
  curved 
  ; 
  

   those 
  at 
  the 
  distal 
  end 
  are 
  short 
  and 
  straight. 
  

  

  As 
  Tornquist 
  has 
  shown, 
  the 
  septum 
  is 
  invisible 
  on 
  the 
  reverse 
  

   side 
  of 
  the 
  rhabdosoma 
  ; 
  in 
  fact 
  it 
  is 
  so 
  reduced 
  that 
  it 
  can 
  scarcely 
  

   be 
  said 
  to 
  be 
  more 
  than 
  a 
  mere 
  fold 
  of 
  the 
  periderm 
  on 
  the 
  obverse 
  

   side. 
  The 
  median 
  fold 
  is 
  not 
  continued 
  to 
  the 
  proximal 
  end 
  of 
  the 
  

   rhabdosoma. 
  

  

  The 
  virgula 
  is 
  distally 
  prolonged, 
  and 
  not 
  infrequently 
  split 
  at 
  

   some 
  point 
  along 
  its 
  length. 
  

  

  No. 
  

  

  Lgth. 
  

  

  L. 
  V. 
  

  

  Width 
  

   opp. 
  I 
  1 
  . 
  

  

  2 
  l 
  . 
  

  

  2 
  2 
  . 
  

  

  No. 
  of 
  

   thecse. 
  

  

  Locality. 
  

  

  l 
  a 
  . 
  

  

  TT 
  

  

  tV 
  

  

  +A 
  

  

  

  

  6+5 
  

  

  Hartfell. 
  

  

  l 
  b 
  . 
  

  

  "2" 
  

  

  

  

  

  

  

  „ 
  

  

  2. 
  

  

  tV? 
  

  

  tV 
  

  

  A 
  

  

  

  TIT 
  

  

  5+4 
  

  

  Belcraig. 
  

  

  3. 
  

  

  tV 
  

  

  7 
  

  

  T? 
  

  

  i 
  

  

  T2" 
  

  

  tV 
  

  

  

  „ 
  

  

  4. 
  

  

  t 
  

  

  

  1 
  

  

  

  

  

  Browgill. 
  

  

  6. 
  

  

  

  

  i 
  

  

  T2" 
  

  

  A 
  

  

  1 
  

  

  TB" 
  

  

  4+3 
  

  

  Tommarp, 
  Skane. 
  

  

  7. 
  

  

  9 
  

  

  A 
  

  

  1 
  

  

  tV 
  

  

  _ 
  1 
  

   TS 
  

  

  4+3 
  

  

  5) 
  J» 
  

  

  11. 
  

  

  1 
  1 
  

  

  T6 
  

  

  ~~ 
  ^ 
  

  

  13" 
  

  

  1 
  

   12" 
  

  

  A 
  

  

  5+4 
  

  

  Kongslena, 
  V. 
  G. 
  

  

  12 
  a 
  . 
  

  

  2 
  

   3" 
  

  

  9 
  

  

  A 
  

  

  1 
  

   T2" 
  

  

  TB 
  

  

  5+4 
  

  

  J> 
  5> 
  5) 
  

  

  12*. 
  

  

  5 
  

   8 
  

  

  ... 
  

  

  A 
  

  

  

  

  4+3 
  

  

  J> 
  >» 
  5> 
  

  

  13 
  a 
  . 
  

  

  A 
  

  

  1 
  

  

  2 
  

  

  1 
  

  

  T2" 
  

  

  T2~ 
  

  

  A 
  

  

  5+4 
  

  

  M 
  » 
  M 
  

  

  13 
  b 
  . 
  

  

  s 
  

  

  "8 
  

  

  3" 
  

  

  tV 
  

  

  A 
  

  

  ? 
  

  

  4+3 
  

  

  » 
  >> 
  >> 
  

  

  14. 
  

  

  

  

  A 
  

  

  T2~ 
  

  

  A 
  

  

  4+4 
  

  

  » 
  )» 
  » 
  

  

  15. 
  

  

  A 
  

  

  1 
  

  

  1 
  

   T2~ 
  

  

  A 
  

  

  A 
  

  

  4+3 
  

  

  >> 
  )> 
  J> 
  

  

  Horizon. 
  — 
  This 
  species 
  has 
  long 
  been 
  recognized 
  as 
  belonging 
  to 
  

   a 
  distinct 
  horizon 
  at 
  the 
  base 
  of 
  the 
  zone 
  of 
  M. 
  spinigerus 
  (JN"ich.), 
  

   both 
  in 
  this 
  country 
  and 
  on 
  the 
  Continent. 
  

  

  British 
  Localities. 
  — 
  Lake 
  District 
  : 
  Browgill. 
  Moffat 
  District 
  : 
  

   DobVs 
  Linn, 
  Belcraig. 
  Ireland 
  : 
  Coalpit 
  Bay. 
  

  

  Cephalogeapttjs 
  petalttm, 
  sp. 
  nov. 
  (PI. 
  XIII. 
  figs. 
  6-9.) 
  

  

  = 
  Diplo(/rap6wS 
  tubular 
  if 
  or 
  mis, 
  Nich., 
  Geol. 
  Mag. 
  1867, 
  pi. 
  vii. 
  figs. 
  12 
  & 
  13. 
  

  

  In 
  1867 
  Prof. 
  Nicholson 
  described 
  a 
  form 
  to 
  which 
  he 
  gave 
  the 
  

   name 
  Diplograptus 
  tubulariformis. 
  Subsequent 
  authors 
  have 
  taken 
  

   this 
  name 
  as 
  a 
  synonym 
  for 
  G. 
  cometa 
  (Gein.), 
  and 
  the 
  description 
  

   given 
  by 
  Nicholson 
  certainly 
  corresponds 
  closely 
  with 
  that 
  species. 
  

   Having 
  examined 
  the 
  specimens, 
  which 
  I 
  believe 
  to 
  be 
  those 
  figured 
  

   by 
  him 
  as 
  D. 
  tubulariformis, 
  I 
  am 
  convinced 
  that 
  they 
  belong 
  to 
  

   three 
  distinct 
  species. 
  The 
  specimens 
  from 
  which 
  figs. 
  12 
  & 
  13 
  

   (op. 
  supra 
  cit.) 
  were 
  drawn 
  belong 
  to 
  a 
  species 
  hitherto 
  undescribed 
  ; 
  

   fig. 
  14 
  is 
  that 
  of 
  a 
  young 
  form 
  of 
  Petalograptus 
  folium 
  (His.); 
  and 
  

   fig. 
  15 
  is 
  probably 
  meant 
  to 
  represent 
  the 
  true 
  Gephalograptus 
  

  

  