﻿which 
  inhabit 
  Jamaica. 
  81 
  

  

  distinct 
  ; 
  outer 
  peritreme 
  moderately 
  expanded, 
  except 
  on 
  the 
  

   left 
  side, 
  which 
  is 
  not 
  reflected 
  : 
  umbilicus 
  small. 
  

  

  Mean 
  divergence 
  about 
  38°; 
  length 
  .62 
  inch; 
  greatest 
  

   breadth 
  .36 
  inch 
  ; 
  least 
  breadth 
  .26 
  inch. 
  

  

  Inhabits 
  New-Hope, 
  Westmoreland. 
  

  

  Cyclostoma 
  Tappanianum. 
  Shell 
  elongate 
  conoid 
  : 
  brown- 
  

   ish 
  orange, 
  with 
  a 
  paler 
  band 
  below 
  the 
  periphery 
  of 
  the 
  last 
  

   whorl, 
  with 
  the 
  columella 
  brown 
  : 
  with 
  crowded 
  strong 
  trans- 
  

   verse 
  striffi, 
  and 
  less 
  strongly 
  impressed 
  spiral 
  striae 
  ; 
  spire 
  

   with 
  the 
  outlines 
  moderately 
  convex, 
  truncated 
  with 
  the 
  loss 
  

  

  of 
  whorls 
  ; 
  remaining 
  whorls 
  four, 
  slightly 
  convex, 
  with 
  

  

  a 
  moderately 
  impressed 
  suture 
  : 
  aperture 
  ovate, 
  acute 
  above, 
  

   with 
  the 
  margin 
  not 
  reflected 
  but 
  sharp 
  : 
  umbilicus 
  indistinct. 
  

  

  Mean 
  divergence 
  about 
  30°; 
  length 
  .41 
  inch; 
  greatest 
  

   breadth 
  .2 
  inch 
  ; 
  least 
  breadth 
  .18 
  inch. 
  

  

  Named 
  in 
  honor 
  of 
  the 
  Hon. 
  Benjamin 
  Tappan, 
  of 
  Ohio. 
  

   This 
  species 
  was 
  found 
  in 
  a 
  lot 
  of 
  Jamaica 
  shells 
  in 
  the 
  col- 
  

   lection 
  of 
  R. 
  Gr. 
  Marshall, 
  Esq., 
  of 
  Morant 
  Bay. 
  

  

  A 
  variety 
  of 
  Cyclostoma 
  papyraceum 
  has 
  the 
  whorls 
  much 
  

   abbreviated 
  ; 
  the 
  last 
  whorl 
  is 
  more 
  abruptly 
  rounded, 
  and 
  the 
  

   aperture 
  is 
  consequently 
  shorter. 
  It 
  may 
  be 
  called 
  abbrevia- 
  

  

  TUM. 
  

  

  Cyclostoma 
  PERPALLmuM. 
  This 
  name 
  is 
  given 
  to 
  "No. 
  

   20," 
  described 
  on 
  page 
  148. 
  Having 
  seen 
  a 
  considerable 
  num- 
  

   ber 
  of 
  specimens, 
  all 
  of 
  which 
  very 
  exactly 
  coincide 
  in 
  their 
  

   characters, 
  I 
  can 
  no 
  longer 
  hesitate 
  to 
  regard 
  it 
  as 
  a 
  good 
  spe- 
  

   cies, 
  although 
  the 
  operculum 
  is 
  yet 
  unknown. 
  

  

  Cyclostoma 
  dubiosum. 
  This 
  species 
  differs 
  in 
  one 
  very 
  

   striking 
  character 
  from 
  C. 
  sutiirale 
  Sowb. 
  : 
  it 
  w^ants 
  the 
  keel 
  

   next 
  below 
  the 
  suture, 
  in 
  the 
  place 
  of 
  which 
  there 
  is 
  a 
  de- 
  

   pression 
  of 
  the 
  upper 
  part 
  of 
  the 
  whorls. 
  We 
  have 
  seen 
  seve- 
  

   ral 
  specimens 
  of 
  this 
  species 
  and 
  many 
  of 
  C. 
  suturale, 
  and 
  all 
  

   of 
  them 
  conform 
  exactly 
  to 
  their 
  respective 
  types. 
  When 
  the 
  

   operculum 
  of 
  C. 
  dubiosum 
  shall 
  have 
  been 
  found, 
  additional 
  

   peculiarities 
  may 
  be 
  discovered. 
  

  

  