﻿JUKES-BKOtVNE 
  : 
  ON 
  THE 
  FA:MILr 
  PEXRICOLIDiE. 
  221 
  

  

  on 
  this 
  point 
  I 
  quite 
  agree 
  ; 
  but 
  whether 
  it 
  should 
  he 
  generically 
  

   separated 
  from 
  Ci/clma 
  only 
  a 
  comparison 
  of 
  the 
  animals 
  can 
  decide. 
  

   At 
  any 
  rate 
  I 
  shall 
  not 
  include 
  Cyclinella 
  in 
  the 
  Petricolidse. 
  

  

  Claudiconcha. 
  — 
  The 
  species 
  referred 
  to 
  this 
  group 
  had 
  always 
  been 
  

   referred 
  to 
  Venernpis, 
  and 
  f 
  ischer 
  in 
  his 
  Manuel 
  de 
  Conchyliologie 
  

   (1887) 
  only 
  separated 
  them 
  as 
  a 
  section 
  of 
  that 
  genus, 
  giving 
  

   V. 
  monstrosa 
  (Chem.) 
  as 
  a 
  single 
  example, 
  Avhich 
  therefore 
  may 
  be 
  

   taken 
  as 
  the 
  type. 
  Dr. 
  Dall, 
  however, 
  regards 
  them 
  as 
  a 
  section 
  

   of 
  Peiricola, 
  remarking, 
  " 
  Lastly 
  we 
  have 
  boring 
  species 
  in 
  which 
  the 
  

   natural 
  inequality 
  of 
  the 
  valves 
  is 
  exaggerated 
  and 
  the 
  margin 
  of 
  the 
  

   right 
  valve 
  in 
  full-grown 
  specimens 
  is 
  irregularly 
  expanded, 
  over- 
  

   lapping 
  that 
  of 
  the 
  left 
  valve 
  which 
  remains 
  normal, 
  and 
  frequently 
  

   forming 
  channels 
  in 
  which 
  the 
  siphons 
  lay 
  or 
  may 
  be 
  extended. 
  For 
  

   these 
  forms, 
  erroneously 
  referred 
  to 
  Venencpis, 
  Fischer 
  has 
  proposed 
  

   the 
  subgeneric 
  name 
  of 
  Claudicoticha.'^ 
  

  

  Dr. 
  Dall 
  does 
  not 
  explain 
  why 
  these 
  species 
  should 
  not 
  he 
  referred 
  

   to 
  Venerupis, 
  hut 
  he 
  asserts 
  them 
  to 
  be 
  boring 
  shells, 
  whereas 
  

   Venenipis 
  is 
  not. 
  He 
  says 
  nothing 
  about 
  the 
  animal, 
  nor 
  does 
  either 
  

   he 
  or 
  Fischer 
  mention 
  any 
  other 
  species 
  beside 
  V. 
  monstrosa. 
  If 
  he 
  

   had 
  evidence 
  that 
  this 
  species 
  was 
  a 
  borer, 
  he 
  should 
  have 
  stated 
  it, 
  

   for 
  the 
  expansion 
  and 
  upturning 
  of 
  the 
  posterior 
  portion 
  of 
  the 
  right 
  

   valve 
  is 
  very 
  difficult 
  to 
  reconcile 
  with 
  the 
  idea 
  that 
  the 
  animal 
  made 
  

   the 
  hole 
  in 
  which 
  it 
  is 
  found 
  ; 
  on 
  the 
  contrary 
  it 
  is 
  just 
  the 
  sort 
  of 
  

   deformation 
  that 
  one 
  would 
  expect 
  in 
  a 
  nestler 
  like 
  Venerupis. 
  

  

  On 
  application 
  to 
  Messrs. 
  8owerby 
  & 
  Fulton 
  they 
  supplied 
  me 
  with 
  

   a 
  specimen 
  of 
  CI. 
  monstrosa, 
  and 
  specimens 
  of 
  two 
  other 
  species 
  which 
  

   they 
  supposed 
  to 
  belong 
  to 
  Claudiconcha. 
  These 
  were 
  V. 
  madreporaria 
  

   and 
  V. 
  Cumingi 
  (Desh.). 
  The 
  last 
  mentioned 
  is, 
  however, 
  unquestion- 
  

   ably 
  a 
  Venerupis, 
  having 
  three 
  distinct 
  teeth 
  in 
  the 
  right 
  valve 
  as 
  well 
  

   as 
  the 
  left. 
  

  

  C. 
  monstrosa 
  has 
  in 
  the 
  left 
  valve 
  three 
  teeth, 
  small 
  nearly 
  equal 
  

   teeth, 
  smooth 
  and 
  pustular, 
  not 
  bifid, 
  and 
  much 
  more 
  resembling 
  

   those 
  of 
  Venenipis 
  than 
  those 
  of 
  Petricola. 
  The 
  right 
  valve 
  has 
  only 
  

   two 
  teeth 
  in 
  the 
  adult, 
  but 
  this 
  may 
  be 
  the 
  result 
  of 
  deformation 
  and 
  

   compression, 
  for 
  I 
  have 
  specimens 
  of 
  V. 
  irus, 
  both 
  young 
  and 
  old, 
  in 
  

   which 
  the 
  anterior 
  tooth 
  is 
  obsolete, 
  so 
  that 
  the 
  number 
  of 
  teeth 
  is 
  

   then 
  the 
  same 
  as 
  in 
  C. 
  monstrosa. 
  

  

  In 
  V. 
  madreporaria 
  the 
  dentition 
  is 
  like 
  that 
  of 
  C. 
  monstrosa, 
  except 
  

   that 
  the 
  left 
  median 
  is 
  broad 
  and 
  is 
  bifid 
  in 
  young 
  shells. 
  In 
  size 
  and 
  

   variability 
  of 
  shape 
  this 
  species 
  resembles 
  V. 
  irus. 
  

  

  So 
  far 
  as 
  I 
  can 
  judge 
  from 
  these 
  few 
  specimens 
  it 
  seems 
  very 
  

   doubtful 
  whether 
  Claudiconcha 
  should 
  be 
  transferred 
  from 
  Venerupis 
  

   to 
  Petricola. 
  

  

  The 
  Cooperella 
  of 
  Cai-penter 
  probably 
  does 
  belong 
  to 
  the 
  Petricolidse, 
  

   but 
  is 
  certainly 
  rather 
  more 
  abnormal 
  than 
  Lucinopsis, 
  which 
  it 
  

   resembles 
  in 
  certain 
  respects. 
  

  

  The 
  shell 
  is 
  small, 
  about 
  half 
  an 
  inch 
  long, 
  very 
  thin, 
  nearly 
  smooth, 
  

   but 
  concentricalljr 
  undulated, 
  and 
  feebly 
  striated; 
  nearly 
  equilateral, 
  

   without 
  lunule 
  or 
  escutcheon. 
  There 
  is 
  a 
  short 
  narrow 
  external 
  

   ligament, 
  which 
  is 
  continuous 
  with 
  a 
  posterior 
  resilium, 
  sunk 
  and 
  

  

  