﻿INTRODUCTION. 
  

  

  Panama 
  Shells. 
  233 
  

  

  than 
  an 
  equal 
  variety 
  of 
  stations. 
  The 
  number 
  of 
  species 
  in 
  

   any 
  region 
  appears 
  to 
  be 
  connected 
  only 
  with 
  climate 
  and 
  

   variety 
  of 
  stations. 
  

  

  It 
  is 
  scarcely 
  necessary 
  to 
  consider 
  the 
  question, 
  whether 
  

   any 
  of 
  the 
  shells 
  on 
  the 
  opposite 
  sides 
  of 
  tropical 
  America 
  

   could 
  have 
  had 
  a 
  common 
  origin. 
  Although 
  in 
  some 
  points 
  

   the 
  Caribbean 
  sea 
  and 
  the 
  Pacific 
  approach 
  within 
  40 
  or 
  50 
  

   miles 
  in 
  a 
  direct 
  line, 
  it 
  is 
  difficult 
  to 
  imagine 
  any 
  adequate 
  

   m^ns 
  of 
  the 
  intercommunication 
  of 
  living 
  marine 
  moUusks. 
  

   If 
  human 
  agency 
  had 
  transplanted 
  any 
  species, 
  we 
  should 
  

   have 
  expected 
  that 
  the 
  edible 
  species 
  would 
  have 
  been 
  selected. 
  

   The 
  following 
  are 
  some 
  of 
  the 
  edible 
  Caribbean 
  species, 
  in 
  the 
  

   order 
  in 
  which 
  they 
  have 
  appeared 
  to 
  us 
  in 
  Jamaica 
  to 
  be 
  

   most 
  commonly 
  used 
  : 
  Trochus 
  pica, 
  Pyrula 
  melongena, 
  

   Ostrea 
  folium, 
  Area 
  Noe, 
  (or 
  an 
  undescribed 
  analogue 
  of 
  this 
  

   species), 
  Strombus 
  gigas, 
  Turbo 
  coelatus, 
  Avicula 
  crocata, 
  

   &c. 
  At 
  Panama, 
  the 
  edible 
  species 
  which 
  we 
  observed 
  are 
  

   in 
  the 
  same 
  order. 
  Area 
  tuberculosa, 
  Venus 
  discors, 
  Ostrea, 
  

   two 
  or 
  three 
  species. 
  Area 
  grandis, 
  Murex 
  radix, 
  Pyrula 
  pa- 
  

   tula, 
  &c. 
  All 
  of 
  these 
  are 
  remarkably 
  distinct, 
  if 
  we 
  except 
  

   the 
  PyrulsB, 
  which 
  are 
  analogues. 
  If 
  it 
  should 
  be 
  supposed 
  

   that 
  the 
  analogues 
  might 
  have 
  had 
  a 
  common 
  origin, 
  it 
  will 
  

   be 
  seen 
  that 
  the 
  entire 
  list 
  of 
  analogues 
  comprises 
  a 
  full 
  pro- 
  

   portion 
  of 
  the 
  rare 
  or 
  minute 
  species, 
  which 
  are 
  not 
  likely 
  to 
  

   have 
  been 
  noticed 
  by 
  the 
  inhabitants. 
  

  

  Birds 
  are 
  commonly 
  called 
  in 
  to 
  aid 
  the 
  imaginary 
  dis- 
  

   persion 
  of 
  species. 
  On 
  the 
  Isthmus, 
  the 
  buzzards 
  are 
  best 
  

   able, 
  with 
  their 
  extraordinary 
  powers 
  of 
  flight, 
  to 
  transport 
  

   them; 
  but 
  their 
  habits 
  of 
  feeding 
  are 
  wholly 
  at. 
  variance 
  

   with 
  such 
  a 
  supposition. 
  The 
  water 
  birds 
  which 
  feed 
  on 
  the 
  

   marine 
  moUusks 
  are 
  unknown 
  to 
  us. 
  But 
  if 
  their 
  agency 
  has 
  

   been 
  effective, 
  it 
  is 
  remarkable 
  that 
  we 
  can 
  identify 
  only 
  one 
  

   species, 
  and 
  that 
  doubtfully, 
  (Crepidula 
  unguiformis), 
  on 
  both 
  

   sides 
  of 
  the 
  Isthmus, 
  and 
  that 
  the 
  habits 
  of 
  this 
  mollusk, 
  at- 
  

  

  JUNE, 
  1852 
  25 
  

  

  