﻿OF 
  CARBONIFEROUS 
  GASTEROPODA. 
  623 
  

  

  number 
  of 
  the 
  keels 
  is 
  the 
  same, 
  with 
  the 
  exception 
  of 
  the 
  strongest 
  

   keel 
  being 
  situated 
  a 
  little 
  higher 
  on 
  the 
  whorl 
  than 
  in 
  the 
  typical 
  

   M. 
  turriculata 
  ; 
  the 
  additional 
  fine 
  keel 
  is 
  visible 
  on 
  the 
  three 
  

   lower 
  whorls. 
  The 
  sutures 
  are 
  rather 
  more 
  prominent 
  than 
  in 
  M. 
  

   turriculata, 
  De 
  Koninck, 
  and 
  also 
  than 
  in 
  my 
  larger 
  specimen. 
  The 
  

   lines 
  of 
  growth 
  are 
  well 
  preserved 
  on 
  the 
  lowest 
  whorl 
  ; 
  they 
  curve 
  

   back 
  to 
  the 
  strongest 
  keel, 
  are 
  invisible 
  between 
  it 
  and 
  the 
  keel 
  

   next 
  below, 
  and 
  then 
  curve 
  forward 
  again. 
  The 
  sinus 
  is 
  probably 
  

   situated 
  between 
  the 
  strongest 
  keel 
  and 
  that 
  next 
  below, 
  but 
  the 
  

   apex 
  and 
  the 
  base 
  of 
  the 
  shell 
  are 
  broken. 
  

  

  Length 
  of 
  fragment 
  consisting 
  of 
  six 
  whorls 
  5| 
  millim., 
  width 
  of 
  

   lowest 
  whorl 
  2| 
  millim. 
  ; 
  it 
  is 
  slightly 
  broken, 
  therefore 
  this 
  measure- 
  

   ment 
  is 
  somewhat 
  less 
  than 
  it 
  would 
  be 
  were 
  the 
  whorl 
  entire. 
  

  

  Locality. 
  Dairy. 
  

  

  Formation. 
  Upper 
  Limestone 
  Series. 
  

  

  MuRCHISONIA 
  (GONIOSTROPHA) 
  ST7BTILISTRIATA, 
  Sp. 
  n0V. 
  (PI. 
  XX. 
  

  

  figs. 
  7, 
  8.) 
  

  

  Shell 
  small, 
  very 
  elongated, 
  consisting 
  of 
  numerous 
  whorls. 
  Each 
  

   whorl 
  has 
  a 
  strong 
  angle 
  a 
  little 
  below 
  the 
  middle, 
  and 
  on 
  this 
  angle 
  

   there 
  is 
  a 
  prominent 
  keel. 
  About 
  midway 
  between 
  this 
  keel 
  and 
  

   the 
  suture 
  there 
  is 
  another 
  keel 
  ; 
  between 
  these 
  keels 
  there 
  are 
  two 
  

   strong 
  threads, 
  and 
  below 
  the 
  lower 
  keel 
  there 
  are 
  one 
  or 
  two 
  strong 
  

   threads 
  between 
  it 
  and 
  the 
  suture. 
  There 
  is 
  also 
  a 
  very 
  faint 
  

   line 
  about 
  midway 
  between 
  the 
  angle 
  and 
  the 
  upper 
  suture. 
  The 
  

   lower 
  part 
  of 
  the 
  whorl 
  is 
  almost 
  flat 
  and 
  slopes 
  rapidly 
  down 
  to 
  the 
  

   suture, 
  which 
  is 
  deep. 
  The 
  upper 
  part 
  of 
  the 
  whorl 
  is 
  slightly 
  con- 
  

   vexo-concave 
  in 
  adult 
  specimens, 
  but 
  in 
  young 
  ones 
  it 
  is 
  more 
  convex, 
  

   the 
  concavity 
  above 
  the 
  angle 
  being 
  hardly 
  discernible. 
  The 
  lines 
  

   of 
  growth 
  are 
  not 
  well 
  preserved 
  on 
  any 
  of 
  the 
  specimens 
  ; 
  on 
  the 
  

   penultimate 
  whorl 
  of 
  the 
  largest 
  specimen 
  there 
  are 
  traces 
  of 
  lines 
  

   of 
  growth 
  curving 
  forward 
  below 
  the 
  strongest 
  keel. 
  This 
  keel 
  

   probably 
  represents 
  the 
  sinus 
  in 
  the 
  outer, 
  lip. 
  The 
  base 
  of 
  all 
  the 
  

   specimens 
  I 
  have 
  seen 
  is 
  broken, 
  therefore 
  the 
  form 
  of 
  the 
  mouth 
  is 
  

   unknown. 
  

  

  There 
  are 
  three 
  specimens 
  of 
  this 
  shell 
  in 
  the 
  collection 
  of 
  Mr. 
  

   Young, 
  Hunterian 
  Museum, 
  Glasgow, 
  and 
  I 
  have 
  a 
  fragment 
  which 
  

   w 
  T 
  as 
  given 
  me 
  by 
  him. 
  The 
  largest 
  specimen 
  (PI. 
  XX. 
  fig. 
  7) 
  con- 
  

   sists 
  of 
  eleven 
  and 
  a 
  half 
  whorls 
  ; 
  both 
  the 
  apex 
  and 
  base 
  are 
  broken. 
  

   Its 
  length 
  is 
  8 
  1 
  millim., 
  width 
  of 
  body- 
  whorl 
  3| 
  millim. 
  Length 
  

   of 
  fragment 
  (PI. 
  XX. 
  fig. 
  8), 
  consisting 
  of 
  three 
  whorls, 
  3| 
  millim. 
  

  

  Locality. 
  Glencart, 
  Dairy. 
  

  

  Formation. 
  Upper 
  Limestone 
  Series. 
  

  

  Section 
  Stegocoslia. 
  

  

  Whorls 
  angular, 
  keeled 
  ; 
  sinus 
  wide, 
  situated 
  on 
  the 
  posterior 
  part 
  

   of 
  the 
  whorl 
  above 
  the 
  angle, 
  umbilicated 
  when 
  young 
  ; 
  inner 
  lip 
  

   reflected 
  on 
  the 
  columella 
  and 
  forming 
  a 
  callosity 
  round 
  the 
  base 
  

   of 
  the 
  pillar, 
  covering 
  the 
  umbilicus 
  in 
  adult 
  specimens. 
  

  

  Q. 
  J. 
  G. 
  S. 
  No. 
  180. 
  2 
  z 
  

  

  