﻿MOLLUSCA. 
  501 
  

  

  67. 
  Cerithium 
  albovaricosum. 
  (Plate 
  XLIV. 
  fig. 
  Q.) 
  

   Ceritliium 
  gracile, 
  Pease 
  (non 
  Laniarck), 
  Proc. 
  Zool. 
  Soc. 
  1800, 
  p. 
  432. 
  

  

  Shell 
  thin, 
  clongate-pyi'amidal, 
  whitish 
  or 
  livid 
  white, 
  sparsely 
  

   spotted 
  between 
  the 
  costte 
  Avith 
  small 
  narrow 
  lines. 
  Whorls 
  about 
  

   14, 
  convex 
  at 
  the 
  sides, 
  separated 
  by 
  a 
  deep, 
  subcanaliculate 
  suture, 
  

   slowly 
  increasing, 
  longitudinally 
  finely 
  costate, 
  and 
  spirally 
  lirate, 
  

   exhibiting 
  at 
  irregular 
  subdistant 
  intervals 
  larger 
  snow-white 
  

   varices. 
  Costre 
  about 
  ten 
  to 
  fifteen 
  on 
  the 
  upper 
  whorls, 
  and 
  

   somewhat 
  nodulous 
  through 
  being 
  crossed 
  by 
  the 
  fine 
  transverse 
  

   lirjB, 
  of 
  which 
  there 
  are 
  about 
  four 
  principal 
  ones, 
  several 
  finer 
  in- 
  

   tervening. 
  Last 
  whorl 
  with 
  a 
  prominent 
  varix 
  at 
  the 
  left 
  side 
  

   opposite 
  the 
  labrum, 
  which 
  is 
  thinnish 
  and 
  somewhat 
  expanded 
  

   and 
  grooved 
  within. 
  Aperture 
  roundish 
  ovate, 
  oblique, 
  contracted 
  

   anteriorly 
  into 
  a 
  narrow 
  also 
  oblique 
  canal, 
  sometimes 
  (not 
  always) 
  

   stained 
  with 
  black. 
  Columella 
  well 
  incurved, 
  covered 
  with 
  a 
  thin 
  

   callosity 
  bearing 
  an 
  elongate 
  transverse 
  tubercle 
  at 
  the 
  upper 
  part. 
  

   Length 
  141 
  millim., 
  diam. 
  44-. 
  

  

  Providence 
  Reef, 
  Mascarenes, 
  in 
  24 
  fms. 
  ; 
  Sandwich 
  Islands 
  

   {Pease). 
  

  

  C. 
  rostratmn 
  of 
  Sowerby 
  is 
  allied 
  to 
  this 
  species, 
  but 
  may 
  be 
  dis- 
  

   tinguished 
  by 
  its 
  more 
  angular 
  whorls, 
  different 
  costa?, 
  less 
  deep 
  

   suture, 
  and 
  the 
  different 
  and 
  more 
  regular 
  dotting 
  between 
  the 
  

   nodules 
  round 
  the 
  middle 
  of 
  the 
  whorls. 
  Specimens 
  from 
  the 
  Sand- 
  

   wich 
  Islands 
  of 
  this 
  species 
  in 
  the 
  British 
  Museum 
  have 
  not 
  a 
  black 
  

   anterior 
  canal, 
  and 
  the 
  costae 
  are 
  rather 
  finer 
  than 
  in 
  the 
  Mascarene 
  

   specimen. 
  

  

  68. 
  Cerithium 
  amirantium. 
  (Plate 
  XLIV. 
  fig. 
  R.) 
  

  

  Shell 
  small, 
  elongate, 
  light 
  pink, 
  faintly 
  dotted 
  with 
  brown. 
  

   Whorls 
  about 
  1 
  2, 
  slightly 
  convex, 
  nodulously 
  costate, 
  spirally 
  lirate, 
  

   exhibiting 
  at 
  distant 
  intervals 
  paler 
  thickish 
  varices. 
  Costae 
  about 
  

   15 
  on 
  trbe 
  upper 
  whorls, 
  crossed 
  by 
  two 
  principal 
  transverse 
  Hrae, 
  

   which 
  are 
  nodulous 
  upon 
  the 
  ribs, 
  giving 
  the 
  whorls 
  a 
  biangulate 
  

   appearance 
  at 
  the 
  sides. 
  In 
  addition 
  to 
  these 
  two 
  there 
  are 
  several 
  

   (about 
  seven) 
  finer 
  lira), 
  but 
  which 
  scarcely 
  form 
  nodules 
  upon 
  the 
  

   costae. 
  The 
  body-whorl 
  has 
  the 
  usual 
  varix 
  on 
  the 
  left 
  side 
  well 
  

   developed, 
  swoUen. 
  The 
  apci'ture 
  is 
  round-ovate, 
  acuminate 
  above 
  

   and 
  prolonged 
  anteriorly 
  into 
  an 
  oblique, 
  short, 
  recurved 
  canal. 
  

   Columella 
  arcuate, 
  coated 
  with 
  a 
  rosy 
  callus, 
  oearing 
  an 
  elongate 
  

   transverse 
  tubercle 
  above. 
  Labrum 
  thickened 
  by 
  a 
  smaU 
  external 
  

   varix. 
  Length 
  15 
  millim., 
  diam. 
  4^. 
  

  

  Darros 
  Island, 
  Amirantes, 
  in 
  22 
  fms. 
  

  

  This 
  pretty 
  little 
  sjiecies 
  agrees 
  with 
  C. 
  fenellam, 
  Sowerby, 
  in 
  

   colour, 
  but 
  is 
  narrower 
  and 
  differently 
  sculptured. 
  

  

  69. 
  Ceritliium 
  ( 
  Rhino 
  clavis) 
  acutinodulosum. 
  

   (Plate 
  XLIV. 
  fig. 
  S.) 
  

  

  Shell 
  elongate-pyramidal, 
  white, 
  spotted 
  with 
  l)rown 
  between 
  

  

  