﻿60 
  Analysis 
  of 
  a 
  certain 
  Group 
  of 
  Species 
  of 
  Cyclostoma. 
  

  

  deeply 
  impressed 
  suture 
  : 
  aperture 
  orbicular, 
  slightly 
  effuse 
  and 
  pointed 
  above 
  ; 
  lip 
  

   scarcely 
  sinuate 
  above, 
  much 
  advanced 
  along 
  the 
  middle 
  of 
  the 
  right 
  side, 
  mod- 
  

   erately 
  thickened 
  : 
  umbilicus 
  four-fifths 
  as 
  wide 
  as 
  the 
  aperture. 
  Operculum 
  with 
  

   a 
  much 
  elevated 
  spiral 
  lamella, 
  in 
  seven 
  or 
  eight 
  whorls, 
  which 
  are 
  much 
  inflect- 
  

   ed 
  but 
  not 
  so 
  curvately 
  as 
  No. 
  1. 
  

  

  Mean 
  divergence 
  about 
  145°; 
  height 
  .6 
  inch; 
  greatest 
  breadth 
  1.08 
  inch 
  ; 
  

   least 
  breadth 
  .85 
  inch. 
  

  

  No. 
  3. 
  Shell 
  with 
  the 
  spire 
  brownish 
  red, 
  and 
  the 
  last 
  whorl 
  white 
  ; 
  with 
  a 
  

   brown 
  epidermis 
  : 
  with 
  the 
  transverse 
  strisB 
  fine 
  and 
  regular 
  on 
  the 
  spire, 
  and 
  very 
  

   irregular 
  on 
  the 
  last 
  whorl 
  ; 
  with 
  fine 
  wrinkles 
  commencing 
  above 
  near 
  the 
  end 
  

   of 
  the 
  penult 
  whorl 
  ; 
  last 
  whorl 
  very 
  coarsely 
  and 
  irregularly 
  wrinkled 
  above, 
  

   nearly 
  or 
  quite 
  smooth 
  beneath 
  ; 
  the 
  umbilical 
  keel 
  is 
  obsolete 
  : 
  spire 
  depressed 
  : 
  

   whorls 
  nearly 
  five 
  ; 
  last 
  whorl 
  flattened 
  above 
  ; 
  with 
  the 
  suture 
  moderately 
  im- 
  

   pressed 
  : 
  aperture 
  orbicular, 
  slightly 
  effuse 
  and 
  pointed 
  above 
  ; 
  lip 
  scarcely 
  sinuate 
  

   above, 
  moderately 
  advanced 
  on 
  the 
  right 
  side 
  : 
  umbilicus 
  about 
  two-thirds 
  as 
  wide 
  

   as 
  the 
  aperture. 
  Operculum 
  with 
  a 
  much 
  elevated 
  spiral 
  lamella, 
  the 
  whorls 
  of 
  

   which, 
  six 
  or 
  seven 
  in 
  number, 
  are 
  saucer-shaped 
  ; 
  that 
  is, 
  reflected, 
  with 
  the 
  inner 
  

   surface 
  concave 
  : 
  the 
  lamella 
  is 
  like 
  that 
  of 
  No. 
  1 
  inverted. 
  

  

  Mean 
  divergence 
  about 
  145° 
  ; 
  height 
  .67 
  inch; 
  greatest 
  breadth 
  1.15 
  inch; 
  

   least 
  breadth 
  .91 
  inch. 
  No. 
  3' 
  differs 
  in 
  having 
  the 
  lower 
  part 
  of 
  the 
  last 
  whorl 
  

   finely 
  wrinkled. 
  

  

  No. 
  4. 
  This 
  resembles 
  No. 
  3, 
  but 
  the 
  wrinkles 
  on 
  the 
  last 
  half 
  of 
  the 
  last 
  

   whorl 
  are 
  somewhat 
  regular, 
  oblique, 
  and 
  very 
  large 
  : 
  the 
  umbilical 
  keel 
  is 
  well 
  

   developed 
  : 
  the 
  umbilicus 
  is 
  only 
  half 
  as 
  wide 
  as 
  the 
  aperture. 
  The 
  operculum 
  is 
  

   unknown. 
  

  

  No. 
  5. 
  Upper 
  whorls 
  horn 
  color 
  or 
  light 
  red 
  ; 
  lower 
  whorls 
  white, 
  with 
  a 
  brown 
  

   epidermis: 
  with 
  the 
  transverse 
  strioe 
  rather 
  fine 
  and 
  irregular 
  ; 
  wrinkles 
  commenc- 
  

   ing 
  on 
  the 
  antepenult 
  whorl, 
  regular, 
  oblique 
  and 
  well 
  defined 
  on 
  the 
  penult 
  whorl, 
  

   sometimes 
  regular 
  on 
  the 
  lower 
  part 
  of 
  the 
  last 
  whorl 
  ; 
  umbilical 
  keel 
  well 
  devel- 
  

   oped 
  : 
  spire 
  somewhat 
  depressed 
  : 
  whorls 
  about 
  four 
  and 
  one-half, 
  scarcely 
  flat- 
  

   tened 
  above, 
  with 
  a 
  well 
  impressed 
  suture 
  : 
  aperture 
  orbicular, 
  slightly 
  effuse 
  and 
  

   pointed 
  at 
  the 
  junction 
  with 
  the 
  penult 
  whorl 
  ; 
  lip 
  rather 
  thin, 
  slightly 
  advanced 
  in 
  

   the 
  right 
  side 
  : 
  umbilicus 
  two-thirds 
  as 
  wide 
  as 
  the 
  aperture. 
  Operculum 
  with 
  a 
  

   spiral 
  lamella 
  of 
  about 
  eight 
  whorls, 
  with 
  the 
  upper 
  margins 
  reflected 
  and 
  expand- 
  

   ed 
  so 
  as 
  to 
  be 
  nearly 
  in 
  contact. 
  

  

  Mean 
  divergence 
  about 
  135° 
  ; 
  height 
  .55 
  inch 
  ; 
  greatest 
  breadth 
  .9 
  inch 
  ; 
  least 
  

   breadth 
  .72 
  inch. 
  

  

  No. 
  6. 
  White, 
  often 
  reddish 
  above 
  ; 
  with 
  a 
  brown 
  epidermis: 
  with 
  the 
  trans- 
  

   verse 
  striae 
  extremely 
  fine, 
  somewhat 
  regular 
  on 
  the 
  upper 
  whorls 
  ; 
  wrinkles 
  com- 
  

   mencing 
  on 
  the 
  antepenult 
  whorl, 
  fine, 
  regular 
  and 
  oblique 
  on 
  the 
  penult 
  whorl 
  and 
  

   at 
  the 
  beginning 
  of 
  the 
  last 
  whorl, 
  on 
  the 
  rest 
  of 
  which 
  they 
  are 
  fine 
  and 
  irregu- 
  

   lar: 
  umbilical 
  keel 
  well 
  developed: 
  spire 
  well 
  elevated: 
  whorls 
  five; 
  last 
  whorl 
  

   slightly 
  depressed 
  above 
  ; 
  suture 
  well 
  impressed: 
  aperture 
  suborbicular, 
  quite 
  effuse 
  

   and 
  pointed 
  above 
  ; 
  lip 
  well 
  thickened, 
  moderately 
  advanced 
  on 
  the 
  right 
  side 
  • 
  

   umbilicus 
  about 
  throe-fifths 
  as 
  wide 
  as 
  the 
  aperture. 
  Operculum 
  slightly 
  concave, 
  

   with 
  a 
  thick 
  spiral 
  lamina 
  of 
  seven 
  or 
  eight 
  whorls, 
  the 
  upper 
  part 
  of 
  which 
  is 
  ex- 
  

  

  