﻿123 
  

  

  ON 
  THE 
  OCCURRENCE 
  IN 
  ENGLAND 
  OF 
  VALVATA 
  MACROSTOMA, 
  

  

  STEENBUCH. 
  

  

  By 
  A. 
  S. 
  Kennakd, 
  F.G.S., 
  and 
  A. 
  "VV. 
  Sielfox, 
  

  

  Read 
  Uth 
  March, 
  1910. 
  

   Valvata 
  3IACR0ST0JIA, 
  Steen., 
  is 
  a 
  well-known 
  and 
  universally 
  

   recognized 
  species, 
  being 
  known 
  in 
  a 
  living 
  state 
  from 
  Sweden, 
  

   Norway, 
  Denmark, 
  Northern 
  Germany, 
  Russia, 
  Finland, 
  and 
  Galicia, 
  

   and 
  in 
  a 
  fossil 
  state 
  from 
  several 
  deposits 
  of 
  Pleistocene 
  age 
  in 
  

   Germany, 
  and 
  from 
  the 
  Holocene 
  of 
  Denmark. 
  Unlike 
  so 
  many 
  of 
  

   the 
  Continental 
  ' 
  species 
  ' 
  of 
  Valvata, 
  it 
  is 
  a 
  species 
  as 
  we 
  understand 
  

   it, 
  and 
  is 
  quite 
  distinct 
  from 
  the 
  polymorphic 
  V. 
  piscinalis. 
  We 
  have 
  

   always 
  considered 
  it 
  a 
  species 
  which 
  was 
  likely 
  to 
  occur 
  in 
  England, 
  

   but 
  all 
  our 
  efforts 
  were 
  fruitless 
  until 
  last 
  year, 
  when 
  one 
  of 
  us 
  

   (A. 
  W. 
  S.) 
  visited 
  the 
  Pevensey 
  Marshes, 
  Sussex, 
  where 
  several 
  

   examples 
  of 
  Valvata 
  were 
  collected 
  at 
  the 
  Eastbourne 
  end 
  of 
  the 
  

   marsh, 
  which 
  in 
  our 
  opinion 
  are 
  undoubtedly 
  V. 
  macrostoma. 
  It 
  may 
  

   be 
  as 
  well 
  to 
  mention 
  that 
  the 
  object 
  of 
  the 
  visit 
  to 
  Pevensey 
  was 
  to 
  

   obtain 
  examples 
  of 
  Planorlis 
  vorticidus, 
  Troschel, 
  and 
  that 
  the 
  search 
  

   for 
  this 
  species 
  was 
  unsuccessful 
  at 
  that 
  time. 
  Pevensey 
  was 
  the 
  only 
  

   locality 
  in 
  these 
  Islands 
  in 
  which 
  P. 
  vorttciilus 
  had 
  been 
  found 
  living, 
  

   though 
  it 
  has 
  since 
  been 
  found 
  alive 
  near 
  Whitlingham 
  Station, 
  near 
  

   Norwich, 
  by 
  one 
  of 
  us 
  (A. 
  S. 
  K). 
  

  

  On 
  the 
  discovery 
  of 
  these 
  recent 
  examples 
  of 
  Valvata 
  niaerostoma 
  

   a 
  further 
  examination 
  was 
  made 
  of 
  all 
  the 
  fossil 
  examples 
  of 
  Valvata 
  

   that 
  we 
  could 
  obtain 
  access 
  to, 
  but 
  no 
  fossil 
  examples 
  were 
  forth- 
  

   coming. 
  However, 
  on 
  examining 
  a 
  series 
  of 
  Pleistocene 
  mollusca 
  from 
  

   Clacton, 
  kindly 
  sent 
  by 
  the 
  Rev. 
  R. 
  Ashington 
  Bullen, 
  an 
  undoubted 
  

   example 
  of 
  V. 
  macrostoma 
  was 
  detected. 
  

  

  AVe 
  have 
  used 
  the 
  specific 
  name 
  macrostoma 
  because 
  there 
  is 
  no 
  

   doubt 
  about 
  this 
  species, 
  but 
  this 
  is 
  not 
  so 
  with 
  regard 
  to 
  V. 
  depressa, 
  

   Pfr., 
  and 
  V. 
  piilchelln, 
  Studer. 
  We 
  are 
  quite 
  unable 
  to 
  separate 
  

   macrostoma 
  from 
  shells 
  labelled 
  pulcliella 
  and 
  depressa 
  which 
  we 
  have 
  

   received 
  from 
  Germany. 
  V. 
  pulchella, 
  Studer, 
  was 
  never 
  described 
  by 
  

   Studer, 
  and 
  there 
  is 
  considerable 
  doubt 
  as 
  to 
  what 
  V. 
  depressa, 
  Pfr., 
  

   really 
  is. 
  By 
  some 
  authors 
  it 
  is 
  considered 
  a 
  variety 
  of 
  piscinalis. 
  

   This, 
  at 
  any 
  rate, 
  is 
  certain, 
  that 
  the 
  V. 
  depressa, 
  Pfr., 
  of 
  German 
  

   authors 
  is 
  quite 
  different 
  from 
  that 
  of 
  French 
  authors, 
  just 
  as 
  

   Planorhis 
  septemgyratus, 
  Ross., 
  is 
  unknown 
  to 
  Fiench 
  authorities, 
  

   who 
  have 
  applied 
  the 
  name 
  to 
  a 
  totally 
  different 
  species, 
  and 
  a 
  similar 
  

   condition 
  of 
  things 
  exists 
  with 
  regai'd 
  to 
  Succinea 
  arenaria, 
  Bouch. 
  

   Chant. 
  

  

  Now 
  that 
  Valvata 
  macrostoma 
  has 
  been 
  recognized 
  in 
  England 
  it 
  is 
  

   hoped 
  that 
  further 
  research 
  will 
  discover 
  it 
  in 
  other 
  localities. 
  

  

  