﻿82 
  Descriptions 
  of 
  Neiu 
  Species 
  and 
  Varieties 
  of 
  Shells, 
  

  

  Stoastoma 
  Piiilippianum. 
  Shell 
  subdiscoidal, 
  convex 
  above 
  : 
  

   pale 
  horn 
  color, 
  subtransparent 
  : 
  surface 
  smooth 
  and 
  shining: 
  

   spire 
  moderately 
  and 
  convexly 
  elevated 
  : 
  whorls 
  three 
  and 
  one- 
  

   half, 
  slightly 
  convex, 
  with 
  a 
  moderately 
  impressed 
  suture 
  ; 
  

   last 
  whorl 
  regularly 
  rounded 
  over 
  the 
  periphery, 
  very 
  slightly 
  

   detached 
  from 
  the 
  penult 
  whorl 
  near 
  the 
  aperture 
  : 
  aperture 
  

   slightly 
  campanulate 
  : 
  labrum 
  slightly 
  produced 
  beyond 
  the 
  

   labium, 
  not 
  scalloped 
  : 
  labium 
  in 
  its 
  upper 
  half 
  a 
  little 
  de- 
  

   tached 
  from 
  the 
  penult 
  whorl, 
  with 
  the 
  lower 
  half 
  extending 
  

   below 
  the 
  penult 
  whorl 
  : 
  umbilicus 
  of 
  moderate 
  size, 
  with 
  the 
  

   spiral 
  lamella 
  excessively 
  developed 
  and 
  usually 
  soldered 
  by 
  

   its 
  exterior 
  edge 
  to 
  the 
  last 
  whorl, 
  forming 
  over 
  the 
  umbilicus 
  

   a 
  large 
  arch, 
  which 
  has 
  an 
  opening 
  rather 
  larger 
  than 
  the 
  

   aperture 
  of 
  the 
  shell. 
  Inhabits 
  Ackendown 
  in 
  Westmoreland. 
  

  

  Mean 
  divergence 
  about 
  130° 
  ; 
  height 
  .055 
  inch 
  ; 
  least 
  

   breadth 
  .09 
  inch 
  ; 
  greatest 
  breadth 
  .075 
  inch. 
  

  

  Stoastoma 
  Agassizianum. 
  Shell 
  subdiscoidal 
  : 
  horn 
  color, 
  

   subtransparent 
  : 
  with, 
  on 
  the 
  last 
  whorl, 
  four 
  very 
  prominent 
  

   sharp 
  carinFE, 
  viz., 
  one 
  along 
  the 
  periphery, 
  and 
  two 
  below 
  

   and 
  one 
  above, 
  the 
  latter 
  appearing 
  only 
  for 
  a 
  short 
  distance 
  

   on 
  the 
  penult 
  whorl 
  ; 
  with 
  a 
  few 
  fine 
  raised 
  spiral 
  lines 
  on 
  the 
  

   upper 
  part 
  of 
  the 
  whorls 
  and 
  between 
  the 
  carinse 
  : 
  spire 
  

   slightly 
  elevated 
  : 
  whorls 
  three 
  and 
  one-half, 
  planulate, 
  with 
  

   a 
  moderately 
  impressed 
  suture; 
  last 
  whorl 
  planulate 
  beneath, 
  

   near 
  the 
  end 
  rapidly 
  descending 
  and 
  slightly 
  detached 
  from 
  

   the 
  penult 
  whorl 
  : 
  aperture 
  very 
  slightly 
  campanulate 
  : 
  labrum 
  

   slightly 
  reflected, 
  rounded, 
  not 
  scalloped 
  : 
  labium 
  : 
  umbi- 
  

   licus 
  of 
  moderate 
  size, 
  with 
  the 
  spiral 
  lamella 
  excessively 
  de- 
  

   veloped 
  and 
  soldered 
  by 
  its 
  exterior 
  edge 
  to 
  the 
  last 
  whorl, 
  

   forming 
  over 
  the 
  umbilicus 
  a 
  large 
  arch, 
  which 
  has 
  an 
  open- 
  

   ing 
  much 
  larger 
  than 
  the 
  aperture 
  of 
  the 
  shell. 
  In 
  the 
  only 
  

   specimen 
  now 
  before 
  me, 
  there 
  is, 
  around 
  the 
  lip 
  within, 
  a 
  

   deposit 
  which 
  contracts 
  the 
  aperture, 
  and 
  rising 
  over 
  the 
  labi- 
  

  

  