﻿which 
  inhabit 
  Jamaica. 
  55 
  

  

  convex, 
  with 
  a 
  well 
  impressed 
  suture 
  : 
  aperture 
  ovate 
  orbicu- 
  

   lar, 
  with 
  two 
  peritremes, 
  of 
  which 
  the 
  outer 
  one 
  is 
  moderately 
  

   expanded 
  and 
  reflected 
  nearly 
  into 
  the 
  plane 
  of 
  the 
  aperture 
  ; 
  

   the 
  inner 
  one 
  is 
  moderately 
  produced 
  and 
  reflected 
  : 
  umbilicus 
  

   very 
  narrow, 
  but 
  extending 
  through 
  the 
  truncate 
  summit. 
  

  

  Mean 
  divergence 
  about 
  37° 
  ; 
  length 
  after 
  truncation 
  .54 
  

   inch 
  : 
  greatest 
  breadth 
  .34 
  inch 
  ; 
  least 
  breadth 
  .23 
  inch. 
  

  

  From 
  Easington. 
  At 
  first 
  sight 
  this 
  species 
  appears 
  like 
  

   C. 
  Adamsi, 
  but 
  is 
  distinguished 
  by 
  being 
  less 
  elongated, 
  by 
  

   the 
  spiral 
  striae, 
  and 
  by 
  the 
  double 
  peritreme. 
  

  

  Cyclostoma 
  tenuistriatum 
  is 
  frequently 
  of 
  a 
  dingy 
  white 
  or 
  

   very 
  pale 
  brown 
  color. 
  

  

  Cyclostoma 
  moclestum 
  Ad. 
  (Cont. 
  Conch.) 
  

  

  A 
  variety 
  of 
  Cyclostoma 
  fimbriatulum 
  has 
  the 
  transverse 
  

   ridges 
  rather 
  more 
  numerous 
  and 
  regular 
  than 
  the 
  type 
  of 
  the 
  

   species, 
  and 
  at 
  their 
  intersection 
  with 
  the 
  spiral 
  ridges 
  more 
  

   or 
  less 
  developed 
  into 
  small 
  opaque 
  white 
  tubercles 
  : 
  its 
  outer 
  

   peritreme 
  is 
  not 
  so 
  wide 
  or 
  scabrous, 
  and 
  is 
  less 
  strongly 
  scal- 
  

   loped, 
  and 
  is 
  less 
  flattened. 
  Its 
  size 
  is 
  less 
  than 
  that 
  of 
  the 
  

   type 
  of 
  the 
  species. 
  It 
  is 
  a 
  local 
  variety, 
  occurring 
  in 
  the 
  

   centre 
  of 
  "Westmoreland, 
  the 
  most 
  western 
  parish, 
  while 
  the 
  

   typical 
  C. 
  fimbriatulum 
  occurs 
  forty 
  miles 
  to 
  the 
  east, 
  in 
  Man- 
  

   chester, 
  near 
  the 
  centre 
  of 
  the 
  island. 
  At 
  the 
  suggestion 
  of 
  

   Mr. 
  Chitty, 
  I 
  propose 
  for 
  it 
  the 
  name 
  of 
  albinodatum. 
  

  

  Another 
  variety 
  of 
  the 
  same 
  species 
  inhabits 
  an 
  interme- 
  

   diate 
  region, 
  the 
  parish 
  of 
  St. 
  Elizabeth's. 
  Yet 
  although 
  ge- 
  

   ographically 
  intermediate 
  between 
  the 
  other 
  two 
  forms, 
  it 
  is 
  

   by 
  no 
  means 
  so 
  in 
  its 
  characters. 
  It 
  is 
  smaller 
  than 
  the 
  var. 
  

   albinodatum, 
  has 
  its 
  peritreme 
  narrower, 
  and 
  the 
  transverse 
  

   ridges 
  are 
  more 
  numerous 
  and 
  regular, 
  in 
  these 
  characters 
  

   diverging 
  yet 
  farther 
  from 
  the 
  type 
  of 
  the 
  species. 
  On 
  the 
  

   other 
  hand, 
  it 
  diverges 
  in 
  the 
  opposite 
  direction, 
  having 
  the 
  

  

  