﻿80 
  Descriptions 
  of 
  New 
  Species 
  and 
  Varieties 
  of 
  Shells, 
  

  

  The 
  operculum 
  is 
  similar 
  to 
  that 
  of 
  C. 
  album, 
  being 
  sub- 
  

   spiral, 
  with 
  oblique 
  striae. 
  

  

  Variety 
  album 
  wants 
  the 
  dark 
  brown 
  color, 
  and 
  has 
  the 
  

   spiral 
  dotted 
  lines 
  more 
  or 
  less 
  indistinct. 
  

  

  Variety 
  virgatum 
  is 
  dingy 
  or 
  pearl 
  white, 
  with 
  the 
  spiral 
  

   dotted 
  lines 
  conspicuous. 
  

  

  This 
  species 
  is 
  named 
  in 
  honor 
  of 
  the 
  botanist 
  M. 
  Chevalier. 
  

  

  Cyclostoma 
  album, 
  var. 
  fuscum, 
  is 
  distinguished 
  by 
  its 
  

   smaller 
  size, 
  brown 
  color, 
  and 
  a 
  less 
  smooth 
  surface. 
  

  

  Cyclostoma 
  Yallahense. 
  This 
  species 
  resembles 
  C. 
  hya- 
  

   cinthinum 
  (p. 
  9), 
  which 
  is 
  probably 
  identical 
  with 
  C. 
  Bank- 
  

   sianum 
  Sowb. 
  But 
  it 
  is 
  smaller 
  and 
  more 
  slender 
  ; 
  the 
  color 
  

   is 
  bluish 
  brown, 
  and 
  does 
  not 
  change 
  by 
  age 
  or 
  exposure 
  into 
  

   orange 
  near 
  the 
  aperture 
  ; 
  the 
  strise 
  are 
  coarser 
  ; 
  the 
  oblique 
  

   indentations 
  are 
  often 
  obsolete. 
  The 
  operculum 
  is 
  similar 
  to 
  

   that 
  of 
  C. 
  hyacinthinum. 
  

  

  Mean 
  divergence 
  about 
  46° 
  ; 
  length 
  .48 
  inch 
  ; 
  greatest 
  

   breadth 
  .32 
  inch 
  ; 
  least 
  breadth 
  .27 
  inch. 
  

  

  Although 
  this 
  shell 
  so 
  much 
  resembles 
  the 
  species 
  with 
  

   which 
  we 
  have 
  compared 
  it, 
  a 
  peculiar 
  type 
  is 
  easily 
  recog- 
  

   nized 
  in 
  it. 
  The 
  two 
  types 
  are 
  geographically 
  remote 
  ; 
  this 
  

   species 
  inhabiting 
  the 
  east 
  end 
  of 
  the 
  island 
  from 
  Yallahs' 
  

   Hill 
  eastward, 
  while 
  the 
  other 
  occurs 
  in 
  the 
  middle 
  of 
  the 
  

   south 
  side 
  (Manchester) 
  and 
  westward. 
  Neither 
  species 
  has 
  

   been 
  found 
  in 
  the 
  intermediate 
  regions. 
  

  

  Cyclostoma 
  sericinum. 
  Shell 
  much 
  elongated, 
  conic 
  : 
  

   silky 
  white, 
  with 
  four 
  spiral 
  series 
  of 
  brown 
  dots, 
  of 
  which 
  

   three 
  appear 
  on 
  the 
  spire 
  ; 
  around 
  the 
  umbilicus 
  is 
  a 
  fifth 
  se- 
  

   ries 
  less 
  distinct 
  : 
  with 
  crowded 
  regular 
  transverse 
  obtuse 
  fine 
  

   raised 
  lines: 
  spire 
  with 
  the 
  outlines 
  moderately 
  convex, 
  trun- 
  

   cated 
  with 
  the 
  loss 
  of 
  two 
  whorls; 
  whorls 
  remaining 
  four 
  and 
  

   one-half, 
  quite 
  convex, 
  with 
  a 
  rather 
  deep 
  suture 
  : 
  aperture 
  

   slightly 
  detached 
  from 
  the 
  penult 
  whorl 
  ; 
  inner 
  peritreme 
  in- 
  

  

  