﻿312 
  

  

  ON 
  AN 
  ABNORMAL 
  SPECIMEN 
  OF 
  COCHLICOPA 
  LUBRICA. 
  

   By 
  E. 
  W. 
  BowELL, 
  M.A., 
  M.R.C.S., 
  etc. 
  

   Bead 
  11th 
  May, 
  1917. 
  

   Whilk 
  searcliing 
  in 
  an 
  old 
  hedgebank 
  at 
  liadlett, 
  in 
  the 
  parish 
  of 
  

   Aldenham, 
  Hertfordshire, 
  on 
  April 
  22iid, 
  1917, 
  I 
  came 
  across 
  the 
  

   remarkable 
  snail 
  which 
  is 
  here 
  described. 
  It 
  was 
  crawling 
  about 
  in 
  

   a 
  tuft 
  of 
  moss, 
  was 
  quite 
  lively, 
  and 
  showed 
  no 
  difficulty 
  in 
  managing 
  

   the 
  large 
  shell. 
  Other 
  species 
  present 
  in 
  the 
  immediate 
  viciuity 
  

   "were 
  Limax 
  agrestis, 
  Avion 
  ater, 
  A. 
  circumscriptus, 
  A. 
  horfensis, 
  

   Pyramidula 
  roUmdata, 
  Theba 
  cauttana, 
  Polita 
  7iitidula, 
  P. 
  cellaria, 
  

   P. 
  alliaria, 
  P. 
  rogersi, 
  P. 
  pura, 
  Clausilia 
  rugosa, 
  and 
  Cochlicopa 
  

   luhrica. 
  

  

  This 
  shell 
  differs 
  from 
  a 
  normal 
  Cochlicopa 
  luhrica 
  in 
  being 
  1 
  Tl 
  mm. 
  

   long 
  and 
  3"4 
  mm. 
  in 
  diameter; 
  it 
  has 
  about 
  seven 
  whorls 
  or 
  rather 
  

   more. 
  The 
  peristome 
  is 
  not 
  thickened 
  or 
  coloured, 
  indicating 
  either 
  

   growth 
  was 
  not 
  complete, 
  or 
  that 
  for 
  some 
  reason 
  the 
  specimen 
  was 
  

   constitutionally 
  unable 
  to 
  produce 
  the 
  usual 
  termination 
  for 
  its 
  shell 
  

   building. 
  At 
  the 
  fourth 
  whorl 
  from 
  the 
  apex 
  the 
  shell 
  shows 
  what 
  

   looks 
  like 
  a 
  mended 
  crack 
  ; 
  if 
  the 
  animal 
  had 
  proceeded 
  to 
  form 
  

   a 
  peristome 
  soon 
  after 
  reaching 
  this 
  point 
  of 
  development 
  it 
  might 
  

   have 
  produced 
  a 
  shell 
  of 
  nearly 
  normal 
  size 
  and 
  shape, 
  and 
  the 
  scar 
  

   may 
  indicate 
  some 
  hesitation 
  in 
  the 
  matter. 
  Comparison 
  of 
  super- 
  

   imposed 
  photographs 
  shows 
  without 
  very 
  much 
  doubt 
  that 
  the 
  apical 
  

   whorls 
  of 
  the 
  present 
  specimen 
  are 
  as 
  near 
  identical 
  in 
  size 
  and 
  form 
  

   with 
  those 
  of 
  a 
  normal 
  luhrica 
  as 
  can 
  be. 
  

  

  Scale 
  line 
  — 
  4 
  mm. 
  

  

  The 
  radula 
  is 
  longer 
  and 
  wider 
  than 
  in 
  luhrica, 
  though 
  this 
  

   enlargement 
  is 
  not 
  in 
  proportion 
  to 
  the 
  magnitude 
  of 
  the 
  shell. 
  The 
  

   central 
  uncus 
  is 
  longer 
  and 
  there 
  are 
  more 
  admedians, 
  more 
  externals, 
  

   and 
  more 
  rows. 
  The 
  total 
  number 
  of 
  unci 
  is 
  therefore 
  increased, 
  

   roughly 
  in 
  proportion 
  to 
  the 
  increased 
  length 
  of 
  the 
  shell. 
  

  

  Length 
  of 
  Data 
  of 
  Radula. 
  

  

  Large 
  specimen 
  

   Normal 
  lubrica 
  from\ 
  

   same 
  locality 
  .../ 
  

  

  