﻿SOME 
  NEW 
  SPECIES 
  OF 
  CARBONIFEROUS 
  GASTEROPODA. 
  619 
  

  

  37. 
  Descriptions 
  of 
  some 
  New 
  Species 
  of 
  Carboniferous 
  Gas- 
  

   teropoda. 
  By 
  Miss 
  Donald, 
  of 
  Stanwix. 
  (Read 
  June 
  19, 
  

   1889.) 
  

  

  (Communicated 
  by 
  J. 
  G. 
  Goodchild, 
  Esq., 
  F.G.S., 
  of 
  the 
  Geological 
  Survey.) 
  

  

  [Plate 
  XX.] 
  

  

  With 
  one 
  exception 
  the 
  Gasteropoda 
  described 
  in 
  tins 
  paper 
  have 
  

   been 
  collected 
  by 
  Mr. 
  John 
  Young, 
  Hunterian 
  Museum, 
  Glasgow. 
  

   The 
  specimens 
  are 
  all 
  very 
  minute 
  and 
  are 
  well 
  preserved, 
  their 
  

   creamy 
  colour 
  giving 
  them 
  the 
  appearance 
  of 
  shells 
  of 
  a 
  much 
  more 
  

   recent 
  date 
  than 
  the 
  Carboniferous 
  period. 
  With 
  the 
  best 
  of 
  ma- 
  

   terials, 
  however, 
  the 
  affinities 
  of 
  the 
  Palaeozoic 
  Gasteropoda 
  are 
  

   always 
  more 
  or 
  less 
  difficult 
  to 
  determine. 
  In 
  this 
  instance 
  

   though 
  the 
  sculpture 
  of 
  the 
  surface 
  is 
  wonderfully 
  well 
  preserved, 
  

   none 
  of 
  the 
  apertures 
  are 
  entire, 
  and 
  the 
  minute 
  size 
  of 
  the 
  shells 
  

   renders 
  it 
  difficult 
  in 
  many 
  instances 
  to 
  discern 
  the 
  lines 
  of 
  growth. 
  

  

  Out 
  of 
  the 
  five 
  Scottish 
  shells 
  three 
  are 
  undoubtedly 
  Murchisonioe, 
  

   one 
  in 
  particular 
  having 
  the 
  band 
  indicating 
  the 
  sinus 
  in 
  the 
  outer 
  

   lip 
  very 
  clearly 
  denned. 
  

  

  With 
  regard 
  to 
  the 
  other 
  two 
  shells, 
  I 
  know 
  of 
  no 
  genus 
  to 
  which 
  

   they 
  may 
  be 
  referred, 
  unless 
  it 
  be 
  Orihonema, 
  Meek 
  and 
  Worthen*. 
  

   The 
  more 
  elongated 
  shell 
  bears 
  some 
  resemblance 
  to 
  species 
  of 
  the 
  

   genus 
  Aclisina, 
  de 
  Koninck 
  t, 
  from 
  which 
  it 
  differs, 
  however, 
  in 
  

   the 
  form 
  of 
  the 
  mouth 
  and 
  the 
  flattened, 
  closely 
  coiled 
  whorls. 
  

  

  Before 
  proceeding 
  to 
  discuss 
  the 
  general 
  characteristics 
  of 
  the 
  

   shells, 
  it 
  may 
  be 
  well 
  to 
  give 
  the 
  original 
  description 
  of 
  the 
  genus 
  

   Ortlionema 
  : 
  — 
  

  

  " 
  Shell 
  elongate, 
  many-whoried 
  ; 
  volutions 
  ornamented 
  with 
  re- 
  

   volving 
  carinas 
  crossed 
  by 
  nearly 
  straight 
  lines 
  of 
  growth 
  ; 
  body- 
  

   whorl 
  short, 
  not 
  produced 
  below 
  ; 
  aperture 
  angular 
  above, 
  slightly 
  

   effuse 
  below 
  ; 
  peristome 
  incomplete 
  ; 
  lip 
  simple, 
  nearly 
  straight 
  ; 
  

   axis 
  imperforate. 
  The 
  shell 
  upon 
  which 
  we 
  propose 
  to 
  found 
  this 
  

   genus 
  has 
  much 
  the 
  appearance 
  of 
  a 
  Murchisonia, 
  but 
  differs 
  in 
  

   being 
  entirely 
  destitute 
  of 
  a 
  spiral 
  band 
  or 
  a 
  sinus 
  in 
  the 
  lip, 
  as 
  

   in 
  that 
  genus 
  and 
  Pleurotomaria, 
  the 
  lines 
  of 
  growth 
  being 
  distinctly 
  

   seen 
  crossing 
  the 
  carinas 
  and 
  the 
  spaces 
  between, 
  without 
  making 
  

   the 
  slightest 
  curve." 
  

  

  In 
  the 
  form 
  of 
  the 
  spire 
  and 
  in 
  ornamentation 
  both 
  the 
  shells 
  agree 
  

   w 
  T 
  ith 
  the 
  above 
  description, 
  the 
  lines 
  of 
  growth 
  also 
  come 
  straight 
  

   down 
  over 
  the 
  keels. 
  With 
  regard 
  to 
  the 
  mouth, 
  it 
  is 
  angular 
  

   above 
  and 
  slightly 
  effuse 
  below, 
  the 
  peristome 
  is 
  incomplete 
  ; 
  the 
  

   pillar-lip, 
  however, 
  seems 
  somewhat 
  more 
  developed 
  than 
  is 
  repre- 
  

  

  * 
  Proc. 
  Acad. 
  Nat. 
  Sci. 
  Phil. 
  1861, 
  p. 
  146. 
  

  

  f 
  Faune 
  du 
  Calc. 
  Carb. 
  de 
  la 
  Belgique, 
  1881, 
  vol. 
  vi. 
  pt. 
  3, 
  p. 
  86. 
  

  

  