﻿46 
  Descriptions 
  of 
  New 
  Species 
  and 
  Vnrieties 
  of 
  Shells, 
  

  

  written 
  A. 
  Qriffiihsii' 
  As 
  this 
  was 
  merely 
  an 
  error 
  in 
  orthog- 
  

   raphy, 
  there 
  can 
  be 
  no 
  objection 
  to 
  the 
  use 
  of 
  the 
  name 
  as 
  

   elsewhere 
  correctly 
  written. 
  

  

  In 
  the 
  following 
  descriptions 
  of 
  operculated 
  land 
  shells, 
  

   the 
  opercula 
  are 
  not 
  described, 
  except 
  when 
  important 
  for 
  the 
  

   diagnosis 
  of 
  the 
  species. 
  We 
  agree 
  with 
  M. 
  Petit, 
  (Journ. 
  de 
  

   Conch. 
  1850, 
  p. 
  39,) 
  who 
  does 
  not 
  find 
  in 
  the 
  opercula 
  of 
  Cy- 
  

   clostoma 
  characters 
  of 
  sufficient 
  importance 
  to 
  establish 
  gen- 
  

   era. 
  Certainly 
  they 
  have 
  not 
  sufficient 
  intrinsic 
  value, 
  and 
  

   it 
  is 
  yet 
  to 
  be 
  shown 
  that 
  they 
  are 
  always 
  expressive 
  of 
  gen- 
  

   eric 
  differences 
  in 
  the 
  soft 
  parts 
  of 
  these 
  animals. 
  A 
  similar 
  

   opinion 
  has 
  been 
  expressed 
  by 
  Mr. 
  Redfield, 
  in 
  his 
  catalogue 
  

   of 
  operculated 
  land 
  shells. 
  Specific 
  differences, 
  however, 
  are 
  

   often 
  well 
  defined 
  in 
  the 
  opercula. 
  

  

  Marginella 
  gracilis. 
  Shell 
  between 
  fusiform 
  and 
  cylin- 
  

   dric, 
  slender 
  : 
  white, 
  with 
  three 
  spiral 
  bands 
  of 
  orange 
  brown 
  

   of 
  which 
  the 
  upper 
  one 
  appears 
  on 
  the 
  spire, 
  a 
  part 
  of 
  the 
  

   middle 
  one 
  is 
  seen 
  in 
  the 
  deflection 
  of 
  the 
  suture 
  in 
  the 
  last 
  

   part 
  of 
  the 
  penult 
  whorl 
  ; 
  the 
  middle 
  band 
  is 
  sometimes 
  in- 
  

   distinct 
  : 
  smooth 
  and 
  shining 
  : 
  apex 
  rather 
  obtuse 
  : 
  spire 
  mod- 
  

   erately 
  lengthened, 
  with 
  the 
  outlines 
  quite 
  curvilinear 
  : 
  whorls 
  

   nearly 
  four, 
  moderately 
  convex, 
  with 
  the 
  suture 
  not 
  very 
  dis- 
  

   tinct 
  ; 
  last 
  whorl 
  long 
  : 
  aperture 
  long 
  and 
  narrow 
  ; 
  lip 
  mod- 
  

   erately 
  thickened, 
  slightly 
  incurved 
  ; 
  varix 
  slightly 
  extended 
  

   on 
  the 
  penult 
  whorl 
  ; 
  with 
  four 
  very 
  oblique 
  plaits. 
  

  

  Length 
  .26 
  inch 
  ; 
  greatest 
  breadth 
  .09 
  inch 
  ; 
  least 
  breadth 
  

   .075 
  inch 
  ; 
  length 
  of 
  aperture 
  .175 
  inch. 
  

  

  This 
  species 
  resembles 
  M. 
  avena 
  Val., 
  (M. 
  varia 
  Soivb.,) 
  

   but 
  is 
  much 
  smaller, 
  and 
  much 
  more 
  slender, 
  and 
  has 
  a 
  long- 
  

   er 
  spire. 
  

  

  BucciNUM 
  PULCHELLUM. 
  Shell 
  ovatc 
  fusiform 
  : 
  pale 
  yel- 
  

   lowish 
  brown, 
  with 
  the 
  spiral 
  ridges 
  dark 
  reddish 
  brown, 
  ex* 
  

  

  