﻿SOWERBr 
  : 
  ON 
  NEW 
  MARINE 
  SHELLS. 
  67 
  

  

  foramen 
  magnum, 
  oblongum, 
  coarctatum, 
  paulo 
  ante 
  medium 
  situm 
  ; 
  

   pagina 
  interna 
  alba, 
  ad 
  marginura 
  acute 
  crenulata, 
  limbo 
  orificii 
  

   cseruleo-albo, 
  anguste 
  nigro 
  marginato. 
  Long. 
  26, 
  lat. 
  17, 
  alt. 
  14 
  mm. 
  

  

  Hai. 
  — 
  Sierra 
  Leone. 
  

  

  This 
  shell 
  has 
  an 
  orifice 
  very 
  like 
  that 
  of 
  F. 
  alahastrites, 
  Reeve, 
  from 
  

   the 
  Cape 
  Yerd 
  Islands, 
  but 
  it 
  is 
  of 
  a 
  much 
  more 
  elevated 
  form, 
  and 
  

   has 
  a 
  much 
  larger 
  number 
  of 
  radiating 
  ribs, 
  which 
  are 
  narrower 
  and 
  

   closer. 
  F. 
  Humphreysi, 
  Reeve, 
  has 
  the 
  same 
  elate 
  form, 
  but 
  a 
  smaller 
  

   orifice, 
  the 
  interior 
  border 
  of 
  which 
  is 
  white 
  without 
  the 
  dark 
  ring. 
  

  

  F. 
  glaucopis, 
  Reeve, 
  another 
  species 
  of 
  the 
  group, 
  has 
  a 
  more 
  depressed 
  

   form 
  and 
  a 
  smaller 
  orifice. 
  Neither 
  of 
  these 
  forms 
  shows 
  any 
  trace 
  of 
  

   the 
  interrupted 
  black 
  rays 
  characteristic 
  of 
  the 
  new 
  species. 
  A 
  number 
  

   of 
  specimens 
  of 
  this 
  species 
  were 
  collected 
  at 
  Sierra 
  Leone 
  by 
  the 
  late 
  

   Admiral 
  Keppel 
  ; 
  they 
  vary 
  somewhat 
  in 
  elevation, 
  and 
  in 
  the 
  number, 
  

   closeness, 
  and 
  nodulosity 
  of 
  the 
  ribs 
  ; 
  but 
  all 
  are 
  characterized 
  by 
  the 
  

   black 
  rays, 
  and 
  by 
  the 
  dark 
  ring 
  bordering 
  the 
  pale, 
  blue 
  limbus 
  

   beneath 
  the 
  orifice. 
  

  

  