﻿which 
  inhabit 
  Jamaica. 
  53 
  

  

  In 
  a 
  second 
  type, 
  variety 
  /3, 
  the 
  shells 
  are 
  more 
  rugose 
  and 
  

   scabrous, 
  but 
  thinner. 
  They 
  are 
  usually 
  of 
  small 
  or 
  medium 
  

   size, 
  and 
  are 
  the 
  most 
  richly 
  colored. 
  A 
  modification 
  of 
  this 
  

   type 
  sometimes 
  occurs 
  with 
  a 
  more 
  elevated 
  spire. 
  

  

  In 
  a 
  third 
  type, 
  variety 
  y, 
  the 
  sculpture 
  is 
  more 
  like 
  that 
  

   of 
  the 
  first, 
  but 
  the 
  outline 
  is 
  more 
  angular, 
  and 
  the 
  shell 
  at- 
  

   tains 
  a 
  great 
  size. 
  The 
  colors 
  are 
  not 
  as 
  vivid 
  as 
  in 
  variety 
  /3. 
  

  

  The 
  figure 
  in 
  Sowb. 
  Thes. 
  (pi. 
  I. 
  fig. 
  17) 
  is 
  more 
  angular, 
  

   and 
  has 
  a 
  more 
  elevated 
  spire 
  than 
  any 
  of 
  the 
  shells 
  which 
  I 
  

   have 
  seen. 
  

  

  The 
  following 
  are 
  the 
  dimensions 
  of 
  these 
  varieties 
  : 
  

  

  Var. 
  a, 
  mean 
  div. 
  91° 
  ; 
  height 
  .53 
  inch 
  ; 
  great, 
  br. 
  .63 
  in. 
  ; 
  least 
  br. 
  .5 
  in, 
  

   " 
  ^, 
  1, 
  " 
  '' 
  97°; 
  " 
  .51 
  " 
  " 
  .67 
  '• 
  " 
  .50 
  " 
  

  

  u 
  (t 
  2, 
  " 
  <' 
  90°; 
  '• 
  .62 
  ''■ 
  " 
  .70 
  " 
  " 
  .56 
  " 
  

  

  " 
  y, 
  " 
  " 
  98°; 
  " 
  .80 
  '' 
  <= 
  .98 
  " 
  " 
  .79 
  " 
  

  

  Fig.inSowb.Tiies.80°; 
  " 
  .82 
  " 
  " 
  .80 
  " 
  '' 
  ? 
  

  

  Cyclostoma 
  sagittiferum. 
  Shell 
  elongate, 
  ovate 
  conic 
  : 
  

   dingy 
  white, 
  with 
  numerous 
  inequidistant 
  dark 
  brown 
  zigzag 
  

   lines, 
  with 
  the 
  four 
  angles 
  which 
  are 
  directed 
  backwards 
  ar- 
  

   ranged 
  in 
  spiral 
  series 
  on 
  stripes 
  of 
  paler 
  brown 
  ; 
  with 
  irregu- 
  

   lar 
  transverse 
  spots 
  of 
  dark 
  brown 
  next 
  below 
  the 
  suture 
  : 
  

   with 
  very 
  crowded 
  fine 
  transverse 
  ridges, 
  which 
  interrupt 
  

   minute 
  spiral 
  elevated 
  lines 
  : 
  apex 
  truncate, 
  with 
  the 
  loss 
  of 
  

   — 
  whorls: 
  spire 
  rather 
  long, 
  with 
  the 
  outlines 
  curvilinear 
  : 
  

   whorls 
  remaining 
  after 
  truncation 
  four, 
  quite 
  convex, 
  with 
  a 
  

   well 
  impressed 
  suture 
  : 
  aperture 
  obliquely 
  ovate, 
  with 
  two 
  

   peritremes 
  ; 
  of 
  which 
  the 
  outer 
  one 
  is 
  moderately 
  produced 
  

   and 
  not 
  reflected 
  posteriorly, 
  but 
  in 
  the 
  rest 
  part 
  is 
  well 
  pro- 
  

   duced, 
  reflected 
  nearly 
  into 
  the 
  plane 
  of 
  the 
  aperture, 
  sinuous 
  

   on 
  the 
  left 
  side 
  anteriorly 
  ; 
  inner 
  peritreme 
  thick, 
  moderately 
  

   produced, 
  slightly 
  reflected 
  : 
  umbilicus 
  very 
  narrow, 
  extend- 
  

   ing 
  through 
  the 
  truncate 
  summit. 
  

   4 
  

  

  