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  Description 
  of 
  Nciu 
  Species 
  and 
  Varieties 
  of 
  Shells, 
  

  

  them 
  species. 
  It 
  is 
  difficult 
  to 
  avoid 
  the 
  conclusion 
  that 
  the 
  

   whole 
  group 
  is 
  more 
  comprehensive 
  than 
  a 
  species, 
  while 
  the 
  

   several 
  local 
  types 
  are 
  of 
  less 
  than 
  specific 
  value, 
  and 
  that 
  it 
  

   is 
  impracticable 
  to 
  recognise 
  in 
  these 
  shells 
  types 
  of 
  the 
  ave- 
  

   rage 
  value 
  of 
  species. 
  

  

  In 
  attempting 
  to 
  classify 
  such 
  of 
  the 
  varieties 
  as 
  are 
  now 
  

   before 
  us, 
  we 
  have 
  been 
  surprised 
  at 
  the 
  great 
  constancy 
  of 
  

   coloring 
  in 
  respect 
  of 
  the 
  kinds 
  and 
  distribution 
  of 
  color. 
  The 
  

   differences 
  of 
  color 
  in 
  a 
  given 
  variety 
  are 
  almost 
  wholly 
  in 
  

   their 
  greater 
  or 
  less 
  depth. 
  

  

  The 
  following 
  varieties 
  are 
  in 
  the 
  collection 
  of 
  Mr. 
  Chitty, 
  

   to 
  whom 
  I 
  am 
  greatly 
  indebted 
  for 
  information 
  respecting 
  

   them. 
  There 
  are 
  a 
  few 
  more 
  in 
  the 
  collection 
  at 
  Amherst 
  

   College. 
  

  

  a. 
  Dark 
  colored 
  varieties. 
  In 
  this 
  group, 
  the 
  dark 
  colors 
  

   fade 
  to 
  a 
  pale 
  brown 
  or 
  cinnamon 
  color. 
  

  

  Var. 
  NiGRESCENs. 
  Shell 
  robust 
  in 
  the 
  lower 
  part, 
  conic 
  

   above 
  : 
  black 
  on 
  the 
  last 
  whorl 
  and 
  on 
  several 
  of 
  the 
  upper 
  

   whorls, 
  fading 
  into 
  brown 
  in 
  the 
  middle, 
  with 
  a 
  dingy 
  white 
  

   stripe 
  anteriorly 
  and 
  a 
  red 
  lip 
  : 
  with 
  a 
  few 
  strise 
  behind 
  the 
  

   lip. 
  In 
  some 
  localities 
  the 
  shell 
  is 
  of 
  medium 
  size 
  and 
  form, 
  

   rather 
  more 
  coarsely 
  striate 
  on 
  the 
  last 
  half 
  of 
  the 
  last 
  whorl, 
  

   and 
  faintly 
  striated 
  on 
  the 
  first 
  half. 
  Inhabits 
  Portland, 
  and 
  

   Manchioneal 
  in 
  St. 
  Thomas-in-the-East. 
  

  

  Var. 
  soLiDA. 
  Shell 
  very 
  thick 
  and 
  robust 
  : 
  very 
  dark 
  or 
  

   blackish 
  brown 
  at 
  both 
  extremities, 
  pale 
  brown 
  along 
  the 
  mid- 
  

   dle, 
  with 
  a 
  pure 
  white 
  widening 
  stripe 
  next 
  below 
  the 
  suture 
  

   of 
  the 
  last 
  whorl 
  ; 
  pink 
  in 
  the 
  lip 
  and 
  behind 
  it 
  : 
  very 
  coarsely 
  

   striated 
  on 
  the 
  last 
  whorl, 
  otherwise 
  feebly 
  striated. 
  In 
  paler 
  

   specimens 
  a 
  faint 
  tinge 
  of 
  red 
  is 
  seen 
  on 
  both 
  extremities, 
  and 
  

   the 
  lip 
  is 
  white. 
  Inhabits 
  the 
  vicinity 
  of 
  Peace 
  R. 
  in 
  the 
  east 
  

   part 
  of 
  Manchester. 
  

  

  Var. 
  LEVIS. 
  Shell 
  robust 
  but 
  rather 
  thin 
  : 
  livid 
  black 
  in 
  

   the 
  upper 
  whorls, 
  pale 
  livid 
  brown 
  along 
  the 
  middle, 
  anteriorly 
  

  

  