﻿58 
  Analysis 
  of 
  a 
  certain 
  Group 
  of 
  Species 
  of 
  Cyclostoma. 
  

  

  column 
  they 
  are 
  grouped 
  under 
  nine 
  types, 
  indicated 
  by 
  the 
  

   Roman 
  letters 
  ; 
  and 
  in 
  the 
  fourth 
  column, 
  under 
  four 
  types, 
  

   indicated 
  b^ 
  capitals. 
  

  

  Equivalent 
  to 
  the 
  whole 
  group 
  thus 
  constituted 
  is 
  a 
  type, 
  

   which 
  appears 
  in 
  C. 
  suturale 
  Soiob. 
  In 
  the 
  former 
  case, 
  the 
  

   group 
  is 
  distributed, 
  in 
  the 
  various 
  subtypes, 
  over 
  most 
  of 
  the 
  

   island. 
  The 
  latter 
  occurs 
  only 
  in 
  the 
  western 
  third 
  of 
  the 
  

   island, 
  and 
  is 
  very 
  uniform 
  in 
  its 
  characters. 
  

  

  If, 
  following 
  the 
  example 
  of 
  some, 
  we 
  should 
  regard 
  all 
  

   types, 
  which 
  are 
  probably 
  original, 
  as 
  requiring 
  to 
  be 
  named 
  

   and 
  described 
  as 
  species, 
  we 
  should 
  soon 
  be 
  involved 
  in 
  an 
  

   endless 
  labyrinth. 
  There 
  would 
  be 
  not 
  less 
  than 
  fifteen 
  spe- 
  

   cies 
  in 
  this 
  group 
  ; 
  the 
  list 
  of 
  species 
  of 
  Cyclostoma 
  inhabit- 
  

   ing 
  Jamaica 
  would 
  be 
  swelled 
  to 
  hundreds 
  ; 
  and 
  the 
  terres- 
  

   trial 
  shells 
  of 
  that 
  island 
  would 
  exceed 
  a 
  thousand 
  species. 
  

   We 
  prefer 
  to 
  treat 
  species 
  as 
  we 
  do 
  genera, 
  and 
  endeavor 
  to 
  

   make 
  them 
  of 
  as 
  nearly 
  equal 
  value 
  as 
  the 
  diversified 
  system 
  

   of 
  nature 
  will 
  permit. 
  We 
  have 
  deemed 
  it 
  useful 
  to 
  present 
  

   an 
  illustration 
  of 
  the 
  actual 
  scheme 
  of 
  nature. 
  

  

  The 
  nine 
  types 
  of 
  the 
  third 
  order, 
  in 
  the 
  foregoing 
  tabic 
  

   appear 
  to 
  be 
  of 
  about 
  the 
  mean 
  value 
  of 
  ordinary 
  species. 
  It 
  

   becomes 
  necessary 
  to 
  assign 
  them 
  names. 
  In 
  the 
  absence 
  of 
  

   the 
  opercula, 
  d 
  and 
  i 
  may 
  be 
  omitted 
  as 
  doubtful. 
  Mr. 
  Sow- 
  

   erby's 
  figure 
  of 
  the 
  operculum 
  of 
  C. 
  Jamaicensis 
  accurately 
  

   represents 
  that 
  of 
  No. 
  18 
  ; 
  and 
  Kijster's 
  figure, 
  the 
  operculum 
  

   of 
  Ts^os. 
  16 
  and 
  17; 
  all 
  of 
  which, 
  notwithstanding 
  some 
  dif- 
  

   ference 
  in 
  the 
  opercula, 
  we 
  had 
  united 
  in 
  one 
  species. 
  Most 
  

   of 
  our 
  specimens 
  are 
  rather 
  too 
  coarsely 
  sculptured 
  to 
  corres- 
  

   pond 
  with 
  the 
  figures 
  given 
  by 
  these 
  authors. 
  Variety 
  16', 
  

   however, 
  corresponds 
  with 
  great 
  exactness 
  to 
  Mr. 
  Sowerby's 
  

   figure. 
  We 
  may 
  therefore 
  conclude 
  that 
  Nos. 
  16-18 
  belong 
  to 
  

   the 
  Chemnitzian 
  species. 
  Our 
  No. 
  1 
  approximates 
  so 
  exactly 
  

   to 
  Mr. 
  Sowerby's 
  figure 
  of 
  C. 
  corrugatum, 
  that 
  we 
  shall 
  pro- 
  

   visionally 
  refer 
  it 
  to 
  that 
  species, 
  although 
  Kuster's 
  figure 
  and 
  

  

  