﻿Catalogue 
  of 
  Shells 
  collected 
  at 
  Panama, 
  luith 
  Notes 
  on 
  

   Synonymy,, 
  Station, 
  and 
  Habitat, 
  by 
  C. 
  B, 
  Adams, 
  PrO" 
  

   fessor 
  of 
  Zoology, 
  Sfc. 
  , 
  in 
  Amherst 
  College, 
  Massachusetts, 
  

   Read 
  before 
  the 
  New- 
  York 
  Lyceum 
  of 
  Natural 
  History^ 
  

   May 
  10, 
  1852. 
  

  

  INTRODUCTION. 
  

  

  f 
  

  

  ON 
  THE 
  MARINE 
  ZOOLOGICAL 
  PROVINCE 
  OP 
  PANAMA. 
  

  

  Panama 
  is 
  situated 
  near 
  the 
  middle 
  of 
  a 
  well 
  defined 
  

   marine 
  zoological 
  province. 
  Perhaps 
  none 
  of 
  the 
  species 
  of 
  

   testaceous 
  MoUusca, 
  (to 
  which 
  part 
  of 
  the 
  Fauna 
  our 
  reniarivs 
  

   are 
  limited,) 
  which 
  inhabit 
  the 
  neighboring 
  seas, 
  exist 
  south 
  

   of 
  22° 
  S. 
  lat., 
  or 
  north 
  of 
  28° 
  N. 
  lat., 
  or 
  west 
  of 
  the 
  Cxallapago 
  

   Islands. 
  All 
  of 
  the 
  few 
  examples 
  of 
  species, 
  which 
  are 
  sup- 
  

   posed 
  to 
  have 
  a 
  wider 
  range, 
  are 
  more 
  or 
  less 
  doubtful. 
  Some 
  

   species 
  which 
  inhabit 
  the 
  northern 
  part 
  of 
  the 
  province, 
  and 
  

   others 
  which 
  inhabit 
  the 
  southern 
  part, 
  may 
  overlap 
  the 
  

   boundaries 
  between 
  this 
  and 
  the 
  adjacent 
  provinces. 
  But 
  

   these 
  species 
  present 
  only 
  the 
  usual 
  difficulty 
  in 
  attempting 
  

   to 
  define 
  the 
  limits 
  of 
  a 
  zoological 
  province. 
  

  

  The 
  most 
  definite 
  and 
  satisfactory 
  method 
  of 
  defining 
  the 
  

   limits 
  of 
  this 
  province, 
  is 
  to 
  place 
  the 
  boundaries 
  at 
  the 
  ex- 
  

   treme 
  limits 
  of 
  the 
  range 
  of 
  about 
  99 
  per 
  cent, 
  of 
  the 
  

   species 
  which 
  inhabit 
  its 
  middle 
  regions. 
  Thus 
  it 
  will 
  be 
  

   seen 
  that 
  several 
  of 
  the 
  species 
  which 
  inhabit 
  Panama 
  also 
  in- 
  

   habit 
  Gruaymas, 
  in 
  the 
  Oulf 
  of 
  California, 
  nearly 
  in 
  28° 
  N, 
  

   lat. 
  ; 
  but 
  none 
  of 
  them 
  inhabit 
  San 
  Diego, 
  which 
  is 
  near 
  33'' 
  

   N. 
  lat. 
  In 
  the 
  same 
  manner 
  the 
  southern 
  limit 
  is 
  found 
  near 
  

   the 
  boundary 
  between 
  Peru 
  and 
  Chili, 
  between 
  22° 
  and 
  24° 
  

   S. 
  lat. 
  

  

  The 
  reason 
  why 
  the 
  range 
  of 
  the 
  species 
  south 
  of 
  the 
  

   equator 
  is 
  several 
  degrees 
  less 
  than 
  on 
  the 
  north 
  side, 
  is 
  ob- 
  

   vious 
  in 
  the 
  Antarctic 
  current, 
  which 
  sets 
  along 
  the 
  west 
  

   coast 
  of 
  South 
  America. 
  In 
  like 
  manner, 
  on 
  the 
  eastern 
  

  

  